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/encrypt/intern/BLO_encrypt.c

@@ -91,7 +91,9 @@ BLO_encrypt(
 	}
 
 #ifdef _WIN32
+#ifndef FREE_WINDOWS
 	RAND_screen();
+#endif
 #endif
 	RAND_bytes(cryptKey, cryptKeyLen);