Allow building with a specific win32 targeted cross compiler (#3305366)

git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@6156 212acab6-be3b-0410-9dea-997c60f758d6

Docs/src/build.but

@@ -100,6 +100,8 @@ To build NSIS Menu, install \W{http://www.wxwidgets.org/}{wxWidgets 2.8}, create
 
 As of NSIS 2.01, the compiler, makensis, also compiles on POSIX platforms. POSIX platforms include Linux, *BSD, Mac OS X and others. Since the generated installer will eventually run on Windows, a \W{http://www.libsdl.org/extras/win32/cross/README.txt}{cross-compiler} is needed in order to compile them.
 
+The command line option XGCC_W32_PREFIX could be used to explicitly select a specific win32 targeted cross compiler. The value of XGCC_W32_PREFIX has to be the prefix of the toolchain. For example XGCC_W32_PREFIX=i686-w64-mingw32 would deploy the win32 targeted MinGW-w64 cross compiler if it is available on the build system.
+
 If no cross-compiler is available, use the following:
 
 \c scons SKIPSTUBS=all SKIPPLUGINS=all SKIPUTILS=all SKIPMISC=all

SCons/Config/gnu

@@ -31,7 +31,7 @@ defenv['ALIGN_FLAG'] = '-Wl,--file-alignment,512'
 defenv['CPP_REQUIRES_STDLIB'] = 1
 defenv['SUBSYS_CON'] = '-Wl,--subsystem,console'
 defenv['MSVCRT_FLAG'] = ''
-defenv['STDCALL'] = '__attribute__((__stdcall__))'
+defenv['STDCALL'] = '"__attribute__((__stdcall__))"'
 
 ### defines
 

SCons/Tools/crossmingw.py

@@ -61,6 +61,11 @@ prefixes = SCons.Util.Split("""
 """)
 
 def find(env):
+    # Explicitly specified toolchain to build Windows executables
+    # takes predominance.
+    prefix = SCons.Script.ARGUMENTS.get('XGCC_W32_PREFIX', None)
+    if prefix:
+        prefixes.insert(0, prefix)
     for prefix in prefixes:
         # First search in the SCons path and then the OS path:
         if env.WhereIs(prefix + 'gcc') or SCons.Util.WhereIs(prefix + 'gcc'):