win32: rudimentary build script for cross compiling

Author: z64me

release-win32.sh

@@ -0,0 +1,3 @@
+mkdir -p bin/
+i686-w64-mingw32.static-gcc -o bin/z64yartool.exe -Os -s -flto -DNDEBUG -Wall -Wextra -Wno-unused-function -lm -std=c99 -pedantic -Iinclude src/*.c
+

src/z64yartool.c

@@ -139,7 +139,11 @@ static int YarDump(const char *input)
 
 	RecipePrint(recipe);
 
+#ifdef _WIN32
+	mkdir(recipe->imageDir);
+#else
 	mkdir(recipe->imageDir, 0777);
+#endif
 	yarEntry = yar->head;
 	for (struct RecipeItem *this = recipe->head
 		; this && yarEntry