#55 Attempt to use clang on windows with special case for i386

i386 is a 32bit platform.
Clang by default is 64bit.
It should be as simple as just requiring clang to build in 32bit mode with -m32.

tests/nim.cfg

@@ -2,9 +2,13 @@
 --gc:arc
 --threads:on
 --define:useMalloc
+--cc:clang
 @if not windows:
-  --cc:clang
   --debugger:native 
   --passc:"-fsanitize=thread -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer" 
   --passl:"-fsanitize=thread -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer"
+@end
+@if windows and i386:
+  --passc:"-m32"
+  --passl:"-m32"
 @end