Support for building bf-blender under windows with gcc (huge thanks to

Florian Eggenburger).

Full instructions are in doc/README.windows-gcc.

Main differences from Florian's patch:

- the 'lib' dir should now be the same level as the 'blender' dir (rather
than being a subdir of 'blender'). This is consistent with the other
platforms that bf-blender supports (tuhopuu will also adopt this convention
hopefully soon).

- the script 'free_windows-env.mk' is no longer needed ... see the
docs about how this is overcome (again, tuhopuu will hopefully
also follow this route soon).

- the dlltool dir has it's own Makefile that builds all of the
needed stub libraries from the dll's in cvs.

source/blender/decrypt/BLO_en_de_cryptHeader.h

@@ -40,6 +40,10 @@ extern "C" {
 
 #include "BLO_sys_types.h"
 
+#ifdef FREE_WINDOWS
+typedef int int32_t;
+#endif
+	
 #define EN_DE_CRYPTHEADERSTRUCTSIZE sizeof(struct BLO_en_de_cryptHeaderStruct)
 
 // Tests showed: pubKeyLen 64, cryptedKeyLen 64 bytes