Added initial AppVeyor config.

build/tools/appveyor.bat

@@ -0,0 +1,39 @@
+goto %TOOLSET%
+
+:msbuild
+cd build\msw
+msbuild /m:2 /v:n /p:Platform=%ARCH% /p:Configuration="%CONFIGURATION%" wx_vc12.sln
+goto :eof
+
+:nmake
+cd build\msw
+call "C:\Program Files (x86)\Microsoft Visual Studio %VS%\VC\vcvarsall.bat" %ARCH%
+nmake -f makefile.vc BUILD=%BUILD%
+goto :eof
+
+:mingw
+cd build\msw
+path C:\MinGW\bin;%path%
+g++ --version
+mingw32-make SHELL=cmd -f makefile.gcc setup_h BUILD=debug SHARED=0 USE_STC=0 USE_RIBBON=0 USE_PROPGRID=0 USE_AUI=0
+mingw32-make SHELL=cmd -j3 -f makefile.gcc BUILD=debug SHARED=0 USE_STC=0 USE_RIBBON=0 USE_PROPGRID=0 USE_AUI=0
+goto :eof
+
+:msys2
+path C:\msys64\%MSYSTEM%\bin;C:\msys64\usr\bin;%path%
+set CHERE_INVOKING=yes
+:: Workaround for "configure: Bad file descriptor"
+perl -i".bak" -pe "s/^test -n \".DJDIR\"/#$&/" configure
+bash -lc "g++ --version"
+bash -lc "CXXFLAGS=-Wno-deprecated-declarations ./configure --enable-debug --disable-xrc && make -j3"
+goto :eof
+
+:cygwin
+C:\cygwin\setup-x86.exe -qnNdO -R C:/cygwin -s http://cygwin.mirror.constant.com -l C:/cygwin/var/cache/setup -P libjpeg-devel -P libpng-devel -P libtiff-devel -P libexpat-devel
+path c:\cygwin\bin;%path%
+set CHERE_INVOKING=yes
+:: Workaround for "configure: Bad file descriptor"
+perl -i".bak" -pe "s/^test -n \".DJDIR\"/#$&/" configure
+bash -lc "g++ --version"
+bash -lc "LDFLAGS=-L/usr/lib/w32api ./configure --enable-debug --disable-shared --disable-html --disable-richtext --disable-stc && make -j3"
+goto :eof