diff --git a/extern/curl/builds/libcurl-vc15-x64-release-static-zlib-static-ipv6-sspi-winssl/lib/libcurl_a.lib b/extern/curl/builds/libcurl-vc15-x64-release-static-zlib-static-ipv6-sspi-winssl/lib/libcurl_a.lib
index db44e222..b092f010 100644
Binary files a/extern/curl/builds/libcurl-vc15-x64-release-static-zlib-static-ipv6-sspi-winssl/lib/libcurl_a.lib and b/extern/curl/builds/libcurl-vc15-x64-release-static-zlib-static-ipv6-sspi-winssl/lib/libcurl_a.lib differ
diff --git a/extern/curl/winbuild/Makefile.vc b/extern/curl/winbuild/Makefile.vc
new file mode 100644
index 00000000..199a65b3
--- /dev/null
+++ b/extern/curl/winbuild/Makefile.vc
@@ -0,0 +1,273 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1999 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+#***************************************************************************
+
+!IF "$(MODE)"=="static"
+TARGET = $(LIB_NAME_STATIC)
+AS_DLL = false
+CFGSET=true
+!ELSEIF "$(MODE)"=="dll"
+TARGET = $(LIB_NAME_DLL)
+AS_DLL = true
+CFGSET=true
+!ELSE
+!MESSAGE Invalid mode: $(MODE)
+
+#######################
+# Usage
+#
+
+!MESSAGE Usage: nmake /f Makefile.vc mode=<static or dll> <options>
+!MESSAGE where <options> is one or many of:
+!MESSAGE   VC=<6,7,8,9,10,11,12,14,15>  - VC versions
+!MESSAGE   WITH_DEVEL=<path>            - Paths for the development files (SSL, zlib, etc.)
+!MESSAGE                                  Defaults to sibbling directory deps: ../deps
+!MESSAGE                                  Libraries can be fetched at http://pecl2.php.net/downloads/php-windows-builds/
+!MESSAGE                                  Uncompress them into the deps folder.
+!MESSAGE   WITH_SSL=<dll or static>     - Enable OpenSSL support, DLL or static
+!MESSAGE   WITH_NGHTTP2=<dll or static> - Enable HTTP/2 support, DLL or static
+!MESSAGE   WITH_CARES=<dll or static>   - Enable c-ares support, DLL or static
+!MESSAGE   WITH_ZLIB=<dll or static>    - Enable zlib support, DLL or static
+!MESSAGE   WITH_SSH2=<dll or static>    - Enable libSSH2 support, DLL or static
+!MESSAGE   WITH_MBEDTLS=<dll or static> - Enable mbedTLS support, DLL or static
+!MESSAGE   ENABLE_IDN=<yes or no>       - Enable use of Windows IDN APIs, defaults to yes
+!MESSAGE                                  Requires Windows Vista or later, or installation from:
+!MESSAGE                                  https://www.microsoft.com/en-us/download/details.aspx?id=734
+!MESSAGE   ENABLE_IPV6=<yes or no>      - Enable IPv6, defaults to yes
+!MESSAGE   ENABLE_SSPI=<yes or no>      - Enable SSPI support, defaults to yes
+!MESSAGE   ENABLE_WINSSL=<yes or no>    - Enable native Windows SSL support, defaults to yes
+!MESSAGE   GEN_PDB=<yes or no>          - Generate Program Database (debug symbols for release build)
+!MESSAGE   DEBUG=<yes or no>            - Debug builds
+!MESSAGE   MACHINE=<x86 or x64>         - Target architecture (default x64 on AMD64, x86 on others)
+!ERROR please choose a valid mode
+
+!ENDIF
+
+!INCLUDE "../lib/Makefile.inc"
+LIBCURL_OBJS=$(CSOURCES:.c=.obj)
+
+!INCLUDE "../src/Makefile.inc"
+
+# tool_hugehelp has a special rule
+CURL_OBJS=$(CURL_CFILES:tool_hugehelp.c=)
+
+CURL_OBJS=$(CURL_OBJS:.c=.obj)
+
+
+# backwards compatible check for USE_SSPI
+!IFDEF USE_SSPI
+ENABLE_SSPI = $(USE_SSPI)
+!ENDIF
+
+# default options
+
+!IFNDEF MACHINE
+# Note: nmake magically changes the value of PROCESSOR_ARCHITECTURE from "AMD64"
+# to "x86" when building in a 32 bit build environment on a 64 bit machine.
+!IF "$(PROCESSOR_ARCHITECTURE)"=="AMD64"
+MACHINE = x64
+!ELSE
+MACHINE = x86
+!ENDIF
+!ENDIF
+
+!IFNDEF ENABLE_IDN
+USE_IDN = true
+!ELSEIF "$(ENABLE_IDN)"=="yes"
+USE_IDN = true
+!ELSEIF "$(ENABLE_IDN)"=="no"
+USE_IDN = false
+!ENDIF
+
+!IFNDEF ENABLE_IPV6
+USE_IPV6 = true
+!ELSEIF "$(ENABLE_IPV6)"=="yes"
+USE_IPV6 = true
+!ELSEIF "$(ENABLE_IPV6)"=="no"
+USE_IPV6 = false
+!ENDIF
+
+!IFNDEF ENABLE_SSPI
+USE_SSPI = true
+!ELSEIF "$(ENABLE_SSPI)"=="yes"
+USE_SSPI = true
+!ELSEIF "$(ENABLE_SSPI)"=="no"
+USE_SSPI = false
+!ENDIF
+
+!IFNDEF ENABLE_WINSSL
+!IF DEFINED(WITH_SSL) || DEFINED(WITH_MBEDTLS)
+USE_WINSSL = false
+!ELSE
+USE_WINSSL = $(USE_SSPI)
+!ENDIF
+!ELSEIF "$(ENABLE_WINSSL)"=="yes"
+USE_WINSSL = true
+!ELSEIF "$(ENABLE_WINSSL)"=="no"
+USE_WINSSL = false
+!ENDIF
+
+CONFIG_NAME_LIB = libcurl
+
+!IF "$(WITH_SSL)"=="dll"
+USE_SSL = true
+SSL     = dll
+!ELSEIF "$(WITH_SSL)"=="static"
+USE_SSL = true
+SSL     = static
+!ENDIF
+
+!IF "$(ENABLE_NGHTTP2)"=="yes"
+# compatibility bit, WITH_NGHTTP2 is the correct flag
+WITH_NGHTTP2 = dll
+USE_NGHTTP2  = true
+NGHTTP2      = dll
+!ELSEIF "$(WITH_NGHTTP2)"=="dll"
+USE_NGHTTP2 = true
+NGHTTP2     = dll
+!ELSEIF "$(WITH_NGHTTP2)"=="static"
+USE_NGHTTP2 = true
+NGHTTP2     = static
+!ENDIF
+
+!IFNDEF USE_NGHTTP2
+USE_NGHTTP2 = false
+!ENDIF
+
+!IF "$(WITH_MBEDTLS)"=="dll" || "$(WITH_MBEDTLS)"=="static"
+USE_MBEDTLS = true
+MBEDTLS     = $(WITH_MBEDTLS)
+!ENDIF
+
+!IF ( "$(USE_SSL)"=="true" && "$(USE_WINSSL)"=="true" ) \
+ || ( "$(USE_SSL)"=="true" && "$(USE_MBEDTLS)"=="true" ) \
+ || ( "$(USE_MBEDTLS)"=="true" && "$(USE_WINSSL)"=="true" )
+!ERROR SSL, MBEDTLS and WINSSL are mutual exclusive options.
+!ENDIF
+
+!IF "$(WITH_CARES)"=="dll"
+USE_CARES = true
+CARES     = dll
+!ELSEIF "$(WITH_CARES)"=="static"
+USE_CARES = true
+CARES     = static
+!ENDIF
+
+!IF "$(WITH_ZLIB)"=="dll"
+USE_ZLIB = true
+ZLIB     = dll
+!ELSEIF "$(WITH_ZLIB)"=="static"
+USE_ZLIB = true
+ZLIB     = static
+!ENDIF
+
+!IF "$(WITH_SSH2)"=="dll"
+USE_SSH2 = true
+SSH2     = dll
+!ELSEIF "$(WITH_SSH2)"=="static"
+USE_SSH2 = true
+SSH2     = static
+!ENDIF
+
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-vc$(VC)-$(MACHINE)
+
+!IF "$(DEBUG)"=="yes"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-debug
+!ELSE
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-release
+!ENDIF
+
+!IF "$(AS_DLL)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-dll
+!ELSE
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-static
+!ENDIF
+
+!IF "$(USE_SSL)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-ssl-$(SSL)
+!ENDIF
+
+!IF "$(USE_MBEDTLS)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-mbedtls-$(MBEDTLS)
+!ENDIF
+
+!IF "$(USE_CARES)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-cares-$(CARES)
+!ENDIF
+
+!IF "$(USE_ZLIB)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-zlib-$(ZLIB)
+!ENDIF
+
+!IF "$(USE_SSH2)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-ssh2-$(SSH2)
+!ENDIF
+
+!IF "$(USE_IPV6)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-ipv6
+!ENDIF
+
+!IF "$(USE_SSPI)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-sspi
+!ENDIF
+
+!IF "$(USE_WINSSL)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-winssl
+!ENDIF
+
+!IF "$(USE_NGHTTP2)"=="true"
+CONFIG_NAME_LIB = $(CONFIG_NAME_LIB)-nghttp2-$(NGHTTP2)
+!ENDIF
+
+!MESSAGE configuration name: $(CONFIG_NAME_LIB)
+
+BUILD_DIR=../builds/$(CONFIG_NAME_LIB)
+LIBCURL_DIROBJ = ..\builds\$(CONFIG_NAME_LIB)-obj-lib
+CURL_DIROBJ = ..\builds\$(CONFIG_NAME_LIB)-obj-curl
+DIRDIST = ..\builds\$(CONFIG_NAME_LIB)\
+
+$(MODE):
+	@SET DIROBJ=$(LIBCURL_DIROBJ)
+	@SET MACRO_NAME=LIBCURL_OBJS
+	@SET OUTFILE=LIBCURL_OBJS.inc
+	@gen_resp_file.bat $(LIBCURL_OBJS)
+
+	@SET DIROBJ=$(CURL_DIROBJ)
+	@SET MACRO_NAME=CURL_OBJS
+	@SET OUTFILE=CURL_OBJS.inc
+	@gen_resp_file.bat $(CURL_OBJS)
+
+	@SET CONFIG_NAME_LIB=$(CONFIG_NAME_LIB)
+	@SET MACHINE=$(MACHINE)
+	@SET USE_NGHTTP2=$(USE_NGHTTP2)
+	@SET USE_IDN=$(USE_IDN)
+	@SET USE_IPV6=$(USE_IPV6)
+	@SET USE_SSPI=$(USE_SSPI)
+	@SET USE_WINSSL=$(USE_WINSSL)
+	@SET RTLIBCFG=static
+# compatibility bit
+	@SET WITH_NGHTTP2=$(WITH_NGHTTP2)
+
+	@$(MAKE) /NOLOGO /F MakefileBuild.vc
+
+copy_from_lib:
+	echo copying .c...
+	FOR %%i IN ($(CURLX_CFILES:/=\)) DO copy %%i ..\src\
diff --git a/extern/curl/winbuild/MakefileBuild.vc b/extern/curl/winbuild/MakefileBuild.vc
new file mode 100644
index 00000000..af3dc00e
--- /dev/null
+++ b/extern/curl/winbuild/MakefileBuild.vc
@@ -0,0 +1,543 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1999 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+#***************************************************************************
+
+###########################################################################
+#
+# Makefile for building libcurl with MSVC 6 through to 15
+#
+# Usage: see usage message below
+#        Should be invoked from winbuild directory
+#        Edit the paths and desired library name
+#        SSL path is only required if you intend compiling
+#        with SSL.
+#
+# This make file leaves the result either a .lib or .dll file
+# in the \lib directory. It should be called from the \lib
+# directory.
+#
+# An option would have been to allow the source directory to
+# be specified, but I saw no requirement.
+#
+# Another option would have been to leave the .lib and .dll
+# files in the "cfg" directory, but then the make file
+# in \src would need to be changed.
+#
+##############################################################
+
+CFGSET=FALSE
+WINBUILD_DIR=`cd`
+ZIP        = zip.exe
+
+# Allow changing C compiler via environment variable CC (default cl.exe)
+# This command macro is not set by default: https://msdn.microsoft.com/en-us/library/ms933742.aspx
+!If "$(CC)" == ""
+CC = cl.exe
+!Endif
+
+!IF "$(VC)"=="6"
+CC_NODEBUG  = $(CC) /O2 /DNDEBUG
+CC_DEBUG    = $(CC) /Od /Gm /Zi /D_DEBUG /GZ
+CFLAGS      = /I. /I../lib /I../include /nologo /W4 /wd4127 /GX /DWIN32 /YX /FD /c /DBUILDING_LIBCURL
+!ELSE
+CC_NODEBUG  = $(CC) /O2 /DNDEBUG
+CC_DEBUG    = $(CC) /Od /D_DEBUG /RTC1 /Z7 /LDd
+CFLAGS      = /I. /I ../lib /I../include /nologo /W4 /wd4127 /EHsc /DWIN32 /FD /c /DBUILDING_LIBCURL
+!ENDIF
+
+LFLAGS     = /nologo /machine:$(MACHINE)
+LNKDLL     = link.exe /DLL
+LNKLIB     = link.exe /lib
+
+CFLAGS_PDB = /Zi
+LFLAGS_PDB = /incremental:no /opt:ref,icf
+
+CFLAGS_LIBCURL_STATIC  = /DCURL_STATICLIB
+
+WIN_LIBS    = ws2_32.lib wldap32.lib advapi32.lib
+
+BASE_NAME              = libcurl
+BASE_NAME_DEBUG        = $(BASE_NAME)_debug
+BASE_NAME_STATIC       = $(BASE_NAME)_a
+BASE_NAME_STATIC_DEBUG = $(BASE_NAME_STATIC)_debug
+
+LIB_NAME_STATIC        = $(BASE_NAME_STATIC).lib
+LIB_NAME_STATIC_DEBUG  = $(BASE_NAME_STATIC_DEBUG).lib
+LIB_NAME_DLL           = $(BASE_NAME).dll
+LIB_NAME_IMP           = $(BASE_NAME).lib
+LIB_NAME_DLL_DEBUG     = $(BASE_NAME_DEBUG).dll
+LIB_NAME_IMP_DEBUG     = $(BASE_NAME_DEBUG).lib
+
+PDB_NAME_STATIC        = $(BASE_NAME_STATIC).pdb
+PDB_NAME_STATIC_DEBUG  = $(BASE_NAME_STATIC_DEBUG).pdb
+PDB_NAME_DLL           = $(BASE_NAME).pdb
+PDB_NAME_DLL_DEBUG     = $(BASE_NAME_DEBUG).pdb
+
+# CURL Command section
+PROGRAM_NAME = curl.exe
+CURL_CFLAGS   =  /I../lib /I../include /nologo /W4 /EHsc /DWIN32 /FD /c
+CURL_LFLAGS   = /nologo /out:$(DIRDIST)\bin\$(PROGRAM_NAME) /subsystem:console /machine:$(MACHINE)
+CURL_RESFLAGS = /i../include
+
+#############################################################
+## Nothing more to do below this line!
+LIBCURL_SRC_DIR = ..\lib
+CURL_SRC_DIR = ..\src
+
+!IFNDEF WITH_DEVEL
+WITH_DEVEL          = ../../deps
+!ENDIF
+DEVEL_INCLUDE  = $(WITH_DEVEL)/include
+DEVEL_LIB      = $(WITH_DEVEL)/lib
+DEVEL_BIN      = $(WITH_DEVEL)/bin
+
+CFLAGS         = $(CFLAGS) /I"$(DEVEL_INCLUDE)"
+LFLAGS         = $(LFLAGS) "/LIBPATH:$(DEVEL_LIB)"
+
+
+!IF "$(WITH_SSL)"=="dll"
+!IF EXISTS("$(DEVEL_LIB)\libssl.lib")
+SSL_LIBS     = libssl.lib libcrypto.lib
+!ELSE
+SSL_LIBS     = libeay32.lib ssleay32.lib
+!ENDIF
+USE_SSL      = true
+SSL          = dll
+!ELSEIF "$(WITH_SSL)"=="static"
+!IF EXISTS("$(DEVEL_LIB)\libssl.lib")
+SSL_LIBS     = libssl.lib libcrypto.lib gdi32.lib user32.lib crypt32.lib
+!ELSE
+SSL_LIBS     = libeay32.lib ssleay32.lib gdi32.lib user32.lib crypt32.lib
+!ENDIF
+USE_SSL      = true
+SSL          = static
+!ENDIF
+
+!IFDEF USE_SSL
+SSL_CFLAGS   = /DUSE_OPENSSL /I"$(DEVEL_INCLUDE)/openssl"
+!IF EXISTS("$(DEVEL_INCLUDE)\openssl\is_boringssl.h")
+SSL_CFLAGS   = $(SSL_CFLAGS) /DHAVE_BORINGSSL
+!ENDIF
+!ENDIF
+
+!IF "$(WITH_NGHTTP2)"=="dll"
+NGHTTP2_CFLAGS   = /DUSE_NGHTTP2
+NGHTTP2_LIBS     = nghttp2.lib
+!ELSEIF "$(WITH_NGHTTP2)"=="static"
+NGHTTP2_CFLAGS   = /DUSE_NGHTTP2 /DNGHTTP2_STATICLIB
+NGHTTP2_LIBS     = nghttp2_static.lib
+!ENDIF
+
+!IF "$(WITH_MBEDTLS)"=="dll" || "$(WITH_MBEDTLS)"=="static"
+USE_MBEDTLS    = true
+MBEDTLS        = $(WITH_MBEDTLS)
+MBEDTLS_CFLAGS = /DUSE_MBEDTLS
+MBEDTLS_LIBS   = mbedtls.lib mbedcrypto.lib mbedx509.lib
+!ENDIF
+
+
+!IF "$(WITH_CARES)"=="dll"
+!IF "$(DEBUG)"=="yes"
+CARES_LIBS     = caresd.lib
+!ELSE
+CARES_LIBS     = cares.lib
+!ENDIF
+USE_CARES      = true
+CARES          = dll
+!ELSEIF "$(WITH_CARES)"=="static"
+!IF "$(DEBUG)"=="yes"
+CARES_LIBS     = libcaresd.lib
+!ELSE
+CARES_LIBS     = libcares.lib
+!ENDIF
+USE_CARES      = true
+CARES          = static
+!ENDIF
+
+!IFDEF USE_CARES
+CARES_CFLAGS   = /DUSE_ARES /I"$(DEVEL_INCLUDE)/cares"
+!ENDIF
+
+!IF "$(WITH_ZLIB)"=="dll"
+ZLIB_LIBS   = zlib.lib
+USE_ZLIB    = true
+ZLIB        = dll
+!ELSEIF "$(WITH_ZLIB)"=="static"
+ZLIB_LIBS   = zlib_a.lib
+USE_ZLIB    = true
+ZLIB        = static
+!ENDIF
+
+!IFDEF USE_ZLIB
+ZLIB_CFLAGS = /DHAVE_ZLIB_H /DHAVE_ZLIB /DHAVE_LIBZ
+!ENDIF
+
+
+!IF "$(WITH_SSH2)"=="dll"
+SSH2_LIBS   = libssh2.lib
+USE_SSH2    = true
+SSH2        = dll
+!ELSEIF "$(WITH_SSH2)"=="static"
+SSH2_LIBS   = libssh2_a.lib user32.lib
+USE_SSH2    = true
+SSH2        = static
+!ENDIF
+
+!IFDEF USE_SSH2
+SSH2_CFLAGS = /DHAVE_LIBSSH2 /DHAVE_LIBSSH2_H /DLIBSSH2_WIN32 /DLIBSSH2_LIBRARY /DUSE_LIBSSH2
+SSH2_CFLAGS = $(SSH2_CFLAGS) /I$(WITH_DEVEL)/include/libssh2
+!ENDIF
+
+
+!IFNDEF USE_IDN
+USE_IDN   = true
+!ELSEIF "$(USE_IDN)"=="yes"
+USE_IDN   = true
+!ENDIF
+
+!IF "$(USE_IDN)"=="true"
+IDN_CFLAGS = $(IDN_CFLAGS) /DUSE_WIN32_IDN /DWANT_IDN_PROTOTYPES
+WIN_LIBS   = $(WIN_LIBS) Normaliz.lib
+!ENDIF
+
+
+!IFNDEF USE_IPV6
+USE_IPV6  = true
+!ELSEIF "$(USE_IPV6)"=="yes"
+USE_IPV6  = true
+!ENDIF
+
+!IF "$(USE_IPV6)"=="true"
+IPV6_CFLAGS = $(IPV6_CFLAGS) /DUSE_IPV6
+!ENDIF
+
+
+!IFNDEF USE_SSPI
+USE_SSPI  = true
+!ELSEIF "$(USE_SSPI)"=="yes"
+USE_SSPI  = true
+!ENDIF
+
+!IF "$(USE_SSPI)"=="true"
+SSPI_CFLAGS = $(SSPI_CFLAGS) /DUSE_WINDOWS_SSPI
+!ENDIF
+
+
+!IFNDEF USE_WINSSL
+!IF "$(USE_SSL)"=="true"
+USE_WINSSL  = false
+!ELSE
+USE_WINSSL  = $(USE_SSPI)
+!ENDIF
+!ELSEIF "$(USE_WINSSL)"=="yes"
+USE_WINSSL  = true
+!ENDIF
+
+
+!IF "$(USE_WINSSL)"=="true"
+!IF "$(USE_SSPI)"!="true"
+!ERROR cannot build with WinSSL without SSPI
+!ENDIF
+SSPI_CFLAGS = $(SSPI_CFLAGS) /DUSE_SCHANNEL
+WIN_LIBS    = $(WIN_LIBS) Crypt32.lib
+!ENDIF
+
+
+!IF "$(GEN_PDB)"=="yes"
+GEN_PDB = true
+!ENDIF
+
+
+!IFDEF EMBED_MANIFEST
+MANIFESTTOOL = mt -manifest $(DIRDIST)\bin\$(PROGRAM_NAME).manifest -outputresource:$(DIRDIST)\bin\$(PROGRAM_NAME);1
+!ENDIF
+
+# Runtime library configuration
+!IF "$(RTLIBCFG)"=="static"
+RTLIB = /MT
+RTLIB_DEBUG = /MTd
+!ELSE
+RTLIB = /MD
+RTLIB_DEBUG  = /MDd
+!ENDIF
+
+!IF "$(MODE)"=="static"
+TARGET = $(LIB_NAME_STATIC)
+CURL_LIBCURL_LIBNAME=$(LIB_NAME_STATIC)
+AS_DLL = false
+CFGSET = true
+!ELSEIF "$(MODE)"=="dll"
+TARGET = $(LIB_NAME_DLL)
+CURL_LIBCURL_LIBNAME=$(LIB_NAME_IMP)
+AS_DLL = true
+CFGSET = true
+!ENDIF
+
+!IF "$(CFGSET)" == "FALSE"
+!ERROR please choose a valid mode
+!ENDIF
+
+
+
+# CURL_XX macros are for the curl.exe command
+
+!IF "$(DEBUG)"=="yes"
+RC_FLAGS = /dDEBUGBUILD=1 /Fo $@ $(LIBCURL_SRC_DIR)\libcurl.rc
+CURL_CC       = $(CC_DEBUG) $(RTLIB_DEBUG)
+CURL_RC_FLAGS = /i../include /dDEBUGBUILD=1 /Fo $@ $(CURL_SRC_DIR)\curl.rc
+!ELSE
+RC_FLAGS = /dDEBUGBUILD=0 /Fo $@ $(LIBCURL_SRC_DIR)\libcurl.rc
+CURL_CC       = $(CC_NODEBUG) $(RTLIB)
+CURL_RC_FLAGS = /i../include /dDEBUGBUILD=0 /Fo $@ $(CURL_SRC_DIR)\curl.rc
+!ENDIF
+
+!IF "$(AS_DLL)" == "true"
+
+LNK       = $(LNKDLL) $(WIN_LIBS) /out:$(LIB_DIROBJ)\$(TARGET)
+!IF "$(DEBUG)"=="yes"
+TARGET    = $(LIB_NAME_DLL_DEBUG)
+LNK       = $(LNK) /DEBUG /IMPLIB:$(LIB_DIROBJ)\$(LIB_NAME_IMP_DEBUG)
+PDB       = $(PDB_NAME_DLL_DEBUG)
+CURL_LIBS = /IMPLIB:$(LIB_DIROBJ)\$(LIB_NAME_IMP_DEBUG)
+!ELSE
+TARGET    = $(LIB_NAME_DLL)
+LNK       = $(LNK)  /IMPLIB:$(LIB_DIROBJ)\$(LIB_NAME_IMP)
+PDB       = $(PDB_NAME_DLL)
+CURL_LIBS = /IMPLIB:$(LIB_DIROBJ)\$(LIB_NAME_IMP)
+!ENDIF
+RESOURCE  = $(LIB_DIROBJ)\libcurl.res
+
+# AS_DLL
+!ELSE
+
+!IF "$(DEBUG)"=="yes"
+TARGET   = $(LIB_NAME_STATIC_DEBUG)
+PDB      = $(PDB_NAME_STATIC_DEBUG)
+!ELSE
+TARGET   = $(LIB_NAME_STATIC)
+PDB      = $(PDB_NAME_STATIC)
+!ENDIF
+LNK      = $(LNKLIB) $(WIN_LIBS) /out:$(LIB_DIROBJ)\$(TARGET)
+CURL_CC  = $(CURL_CC) $(CFLAGS_LIBCURL_STATIC)
+
+# AS_DLL
+!ENDIF
+
+!IF "$(USE_SSL)"=="true"
+CFLAGS = $(CFLAGS) $(SSL_CFLAGS)
+LFLAGS = $(LFLAGS) $(SSL_LFLAGS) $(SSL_LIBS)
+!ENDIF
+
+!IF "$(USE_MBEDTLS)"=="true"
+CFLAGS = $(CFLAGS) $(MBEDTLS_CFLAGS)
+LFLAGS = $(LFLAGS) $(MBEDTLS_LFLAGS) $(MBEDTLS_LIBS)
+!ENDIF
+
+!IF "$(USE_CARES)"=="true"
+CFLAGS = $(CFLAGS) $(CARES_CFLAGS)
+LFLAGS = $(LFLAGS) $(CARES_LFLAGS) $(CARES_LIBS)
+!ENDIF
+
+!IF "$(USE_ZLIB)"=="true"
+CFLAGS = $(CFLAGS) $(ZLIB_CFLAGS)
+LFLAGS = $(LFLAGS) $(ZLIB_LFLAGS) $(ZLIB_LIBS)
+!ENDIF
+
+!IF "$(USE_SSH2)"=="true"
+CFLAGS = $(CFLAGS) $(SSH2_CFLAGS)
+LFLAGS = $(LFLAGS) $(SSH2_LFLAGS) $(SSH2_LIBS)
+!ENDIF
+
+!IF "$(USE_IDN)"=="true"
+CFLAGS = $(CFLAGS) $(IDN_CFLAGS)
+!ENDIF
+
+!IF "$(USE_IPV6)"=="true"
+CFLAGS = $(CFLAGS) $(IPV6_CFLAGS)
+!ENDIF
+
+!IF "$(USE_SSPI)"=="true"
+CFLAGS = $(CFLAGS) $(SSPI_CFLAGS)
+!ENDIF
+
+!IF "$(USE_NGHTTP2)"=="true"
+CFLAGS = $(CFLAGS) $(NGHTTP2_CFLAGS)
+LFLAGS = $(LFLAGS) $(NGHTTP2_LFLAGS) $(NGHTTP2_LIBS)
+!ENDIF
+
+!IF "$(GEN_PDB)"=="true"
+CFLAGS = $(CFLAGS) $(CFLAGS_PDB) /Fd"$(LIB_DIROBJ)\$(PDB)"
+LFLAGS = $(LFLAGS) $(LFLAGS_PDB)
+!ENDIF
+
+LIB_DIROBJ = ..\builds\$(CONFIG_NAME_LIB)-obj-lib
+CURL_DIROBJ = ..\builds\$(CONFIG_NAME_LIB)-obj-curl
+DIRDIST = ..\builds\$(CONFIG_NAME_LIB)\
+
+#
+# curl.exe
+#
+CURL_LINK = link.exe /incremental:no /libpath:"$(DIRDIST)\lib"
+
+#!IF "$(CFG)" == "release-ssh2-ssl-dll-zlib"
+#TARGET   = $(LIB_NAME_STATIC)
+#LNK      = $(LNKLIB) $(WINLIBS) $(SSLLIBS) $(ZLIBLIBS)  $(SSH2LIBS) $(SSL_LFLAGS) $(ZLIB_LFLAGS) $(LFLAGSSSH) /out:$(LIB_DIROBJ)\$(TARGET)
+#CC       = $(CCNODBG) $(RTLIB) $(SSL_CFLAGS) $(ZLIB_CFLAGS) $(CFLAGSLIB)  $(SSH2_CFLAGS)
+#CFGSET   = TRUE
+#!ENDIF
+
+#######################
+# Only the clean target can be used if a config was not provided.
+#
+!IF "$(CFGSET)" == "FALSE"
+clean:
+	@-erase /s *.dll 2> NUL
+	@-erase /s *.exp 2> NUL
+	@-erase /s *.idb 2> NUL
+	@-erase /s *.lib 2> NUL
+	@-erase /s *.obj 2> NUL
+	@-erase /s *.pch 2> NUL
+	@-erase /s *.pdb 2> NUL
+	@-erase /s *.res 2> NUL
+!ELSE
+# A mode was provided, so the library can be built.
+#
+!include CURL_OBJS.inc
+!include LIBCURL_OBJS.inc
+
+!IF "$(AS_DLL)" == "true"
+LIB_OBJS = $(LIBCURL_OBJS) $(RESOURCE)
+!ELSE
+LIB_OBJS = $(LIBCURL_OBJS)
+!ENDIF
+
+EXE_OBJS = $(CURL_OBJS) $(CURL_DIROBJ)\curl.res
+
+all : $(TARGET) $(PROGRAM_NAME)
+
+package: $(TARGET)
+	@cd $(DIRDIST)
+	@-$(ZIP) -9 -q -r ..\$(CONFIG_NAME_LIB).zip .>nul 2<&1
+	@cd $(MAKEDIR)
+
+$(TARGET): $(LIB_OBJS) $(LIB_DIROBJ) $(DISTDIR)
+	@echo Using SSL: $(USE_SSL)
+	@echo Using NGHTTP2: $(USE_NGHTTP2)
+	@echo Using c-ares: $(USE_CARES)
+	@echo Using SSH2: $(USE_SSH2)
+	@echo Using ZLIB: $(USE_ZLIB)
+	@echo Using IDN:  $(USE_IDN)
+	@echo Using IPv6: $(USE_IPV6)
+	@echo Using SSPI: $(USE_SSPI)
+	@echo Using WinSSL: $(USE_WINSSL)
+	@echo CFLAGS:     $(CFLAGS)
+	@echo LFLAGS:     $(LFLAGS)
+	@echo GenPDB:     $(GEN_PDB)
+	@echo Debug:      $(DEBUG)
+	@echo Machine:    $(MACHINE)
+	$(LNK) $(LFLAGS) $(LIB_OBJS)
+	@echo Copying libs...
+	@if exist $(LIB_DIROBJ)\$(LIB_NAME_DLL) copy $(LIB_DIROBJ)\$(LIB_NAME_DLL)       $(DIRDIST)\bin\ /y >nul 2<&1
+	@if exist $(LIB_DIROBJ)\$(LIB_NAME_STATIC) copy $(LIB_DIROBJ)\$(LIB_NAME_STATIC)    $(DIRDIST)\lib\ /y >nul 2<&1
+	@if exist $(LIB_DIROBJ)\$(LIB_NAME_DLL_DEBUG) copy $(LIB_DIROBJ)\$(LIB_NAME_DLL_DEBUG) $(DIRDIST)\bin\ /y >nul 2<&1
+	@if exist $(LIB_DIROBJ)\$(LIB_NAME_STATIC_DEBUG) copy $(LIB_DIROBJ)\$(LIB_NAME_STATIC_DEBUG) $(DIRDIST)\lib\ /y >nul 2<&1
+	@if exist $(LIB_DIROBJ)\$(LIB_NAME_IMP) copy $(LIB_DIROBJ)\$(LIB_NAME_IMP)       $(DIRDIST)\lib\ /y >nul 2<&1
+	@if exist $(LIB_DIROBJ)\$(LIB_NAME_IMP_DEBUG) copy $(LIB_DIROBJ)\$(LIB_NAME_IMP_DEBUG) $(DIRDIST)\lib >nul 2<&1
+	@-copy $(LIB_DIROBJ)\*.exp                 $(DIRDIST)\lib /y >nul 2<&1
+	@-copy $(LIB_DIROBJ)\*.pdb                 $(DIRDIST)\lib /y >nul 2<&1
+	@-copy ..\include\curl\*.h   $(DIRDIST)\include\curl\ /y  >nul 2<&1
+
+$(LIB_OBJS): $(LIB_DIROBJ) $(DIRDIST)
+
+$(DIRDIST):
+	@if not exist "$(DIRDIST)\bin" mkdir $(DIRDIST)\bin
+	@if not exist "$(DIRDIST)\include" mkdir $(DIRDIST)\include
+	@if not exist "$(DIRDIST)\include\curl" mkdir $(DIRDIST)\include\curl
+	@if not exist "$(DIRDIST)\lib" mkdir $(DIRDIST)\lib
+
+$(LIB_DIROBJ):
+	@if not exist "$(LIB_DIROBJ)" mkdir $(LIB_DIROBJ)
+	@if not exist "$(LIB_DIROBJ)\vauth" mkdir $(LIB_DIROBJ)\vauth
+	@if not exist "$(LIB_DIROBJ)\vtls" mkdir $(LIB_DIROBJ)\vtls
+
+$(CURL_DIROBJ):
+	@if not exist "$(CURL_DIROBJ)" mkdir $(CURL_DIROBJ)
+# we need a lib dir for the portability functions from libcurl
+# we use the .c directly here
+	@if not exist "$(CURL_DIROBJ)" mkdir $(CURL_DIROBJ)\lib
+
+.SUFFIXES: .c .obj .res
+
+{$(LIBCURL_SRC_DIR)\}.c{$(LIB_DIROBJ)\}.obj:
+	$(CURL_CC) $(CFLAGS) /Fo"$@"  $<
+
+{$(LIBCURL_SRC_DIR)\vauth\}.c{$(LIB_DIROBJ)\vauth\}.obj:
+	$(CURL_CC) $(CFLAGS) /Fo"$@"  $<
+
+{$(LIBCURL_SRC_DIR)\vtls\}.c{$(LIB_DIROBJ)\vtls\}.obj:
+	$(CURL_CC) $(CFLAGS) /Fo"$@"  $<
+
+$(LIB_DIROBJ)\libcurl.res: $(LIBCURL_SRC_DIR)\libcurl.rc
+	rc $(RC_FLAGS)
+
+#
+# curl.exe
+#
+
+
+!IF "$(MODE)"=="static"
+!IF "$(DEBUG)"=="yes"
+CURL_LIBCURL_LIBNAME=$(LIB_NAME_STATIC_DEBUG)
+!ELSE
+CURL_LIBCURL_LIBNAME=$(LIB_NAME_STATIC)
+!ENDIF
+!ELSEIF "$(MODE)"=="dll"
+!IF "$(DEBUG)"=="yes"
+CURL_LIBCURL_LIBNAME=$(LIB_NAME_IMP_DEBUG)
+!ELSE
+CURL_LIBCURL_LIBNAME=$(LIB_NAME_IMP)
+!ENDIF
+!ENDIF
+
+CURL_FROM_LIBCURL=$(CURL_DIROBJ)\tool_hugehelp.obj \
+ $(CURL_DIROBJ)\nonblock.obj \
+ $(CURL_DIROBJ)\strtoofft.obj \
+ $(CURL_DIROBJ)\warnless.obj
+ 
+$(PROGRAM_NAME): $(CURL_DIROBJ) $(CURL_FROM_LIBCURL) $(EXE_OBJS)
+	$(CURL_LINK) $(CURL_LFLAGS) $(CURL_LIBCURL_LIBNAME) $(WIN_LIBS) $(CURL_FROM_LIBCURL) $(EXE_OBJS)
+	$(MANIFESTTOOL)
+
+{$(CURL_SRC_DIR)\}.c{$(CURL_DIROBJ)\}.obj:
+	$(CURL_CC) $(CURL_CFLAGS) /Fo"$@"  $<
+
+$(CURL_DIROBJ)\tool_hugehelp.obj: $(CURL_SRC_DIR)\tool_hugehelp.c
+	$(CURL_CC) $(CURL_CFLAGS) /Zm200 /Fo"$@" $(CURL_SRC_DIR)\tool_hugehelp.c
+$(CURL_DIROBJ)\nonblock.obj: ../lib/nonblock.c
+	$(CURL_CC) $(CURL_CFLAGS) /Fo"$@" ../lib/nonblock.c
+$(CURL_DIROBJ)\strtoofft.obj: ../lib/strtoofft.c
+	$(CURL_CC) $(CURL_CFLAGS) /Fo"$@" ../lib/strtoofft.c
+$(CURL_DIROBJ)\warnless.obj: ../lib/warnless.c
+	$(CURL_CC) $(CURL_CFLAGS) /Fo"$@" ../lib/warnless.c
+$(CURL_DIROBJ)\curl.res: $(CURL_SRC_DIR)\curl.rc
+	rc $(CURL_RC_FLAGS)
+
+!ENDIF  # End of case where a config was provided.
diff --git a/extern/curl/winbuild/build.bat b/extern/curl/winbuild/build.bat
index fca5452b..f20fe33b 100644
--- a/extern/curl/winbuild/build.bat
+++ b/extern/curl/winbuild/build.bat
@@ -1 +1 @@
-nmake /f Makefile.vc mode=static VC=15 ENABLE_WINSSL=yes ENABLE_SSPI=yes MACHINE=x64 WITH_ZLIB=static WITH_DEVEL=../deps
+nmake /f Makefile.vc mode=static VC=15 RTLIBCFG=static ENABLE_WINSSL=yes ENABLE_SSPI=yes MACHINE=x64 WITH_ZLIB=static WITH_DEVEL=../deps