mingw: Build for 32-bit targets.

We had a request for 64-bit Windows binaries at some point, but
win32 is more broadly compatible. Since everything's broken,
let's concentrate on that and add rules to generate a separate
opusfile-${version}-win64 package later.

Author: rillian

mingw/Makefile

@@ -78,7 +78,7 @@ opus_BUILD: $(opus_DIR)
 	$(MAKE) -C $< install
 
 ssl_BUILD: $(ssl_DIR)
-	cd $< && ./Configure shared mingw64 no-asm \
+	cd $< && ./Configure shared mingw no-asm \
 	  --prefix=$(CURDIR) \
 	  --cross-compile-prefix=$(TOOL_PREFIX)-
 	$(MAKE) -C $< depend