Build: add scripts to build dependencies for Windows and macOS.

Note these are intended for platform maintainers, we do not intend to
support users making their own builds with these. For that precompiled
libraries from lib/ should be used.

Implemented by Martijn Berger, Ray Molenkamp and Brecht Van Lommel.

Differential Revision: https://developer.blender.org/D2753

build_files/build_environment/patches/python.diff

@@ -0,0 +1,40 @@
+--- pcbuild/build.bat   2016-05-21 09:53:55 -0600
++++ pcbuild/build.bat   2016-05-21 09:56:16 -0600
+@@ -59,6 +59,7 @@
+ if "%~1"=="-h" goto Usage
+ if "%~1"=="-c" (set conf=%2) & shift & shift & goto CheckOpts
+ if "%~1"=="-p" (set platf=%2) & shift & shift & goto CheckOpts
++if "%~1"=="-k" (set vs_toolset=%2) & shift & shift & goto CheckOpts
+ if "%~1"=="-r" (set target=Rebuild) & shift & goto CheckOpts
+ if "%~1"=="-t" (set target=%2) & shift & shift & goto CheckOpts
+ if "%~1"=="-d" (set conf=Debug) & shift & goto CheckOpts
+@@ -126,7 +126,7 @@
+
+ :Kill
+ echo on
+-msbuild "%dir%\pythoncore.vcxproj" /t:KillPython %verbose%^
++msbuild "%dir%\pythoncore.vcxproj" /t:KillPython %verbose% /p:PlatformToolset=%vs_toolset%^
+  /p:Configuration=%conf% /p:Platform=%platf%^
+  /p:KillPython=true
+
+@@ -95,7 +96,7 @@
+ rem batch is, shall we say, "lackluster"
+ echo on
+ msbuild "%dir%pcbuild.proj" /t:%target% %parallel% %verbose%^
+- /p:Configuration=%conf% /p:Platform=%platf%^
++ /p:Configuration=%conf% /p:Platform=%platf% /p:PlatformToolset=%vs_toolset%^
+  /p:IncludeExternals=%IncludeExternals%^
+  /p:IncludeSSL=%IncludeSSL% /p:IncludeTkinter=%IncludeTkinter%^
+  /p:UseTestMarker=%UseTestMarker%^
+
+--- pcbuild/sqlite3.vcxproj	2015-12-06 18:39:10 -0700
++++ pcbuild/sqlite3.vcxproj	2016-11-02 09:25:56 -0600
+@@ -43,7 +43,7 @@
+   <Import Project="python.props" />
+   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+   <PropertyGroup Label="Configuration">
+-    <ConfigurationType>DynamicLibrary</ConfigurationType>
++    <ConfigurationType>StaticLibrary</ConfigurationType>
+     <CharacterSet>NotSet</CharacterSet>
+   </PropertyGroup>
+   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />