makes raylib and stb_rect_pack free of libc

vendor/stb/rect_pack/stb_rect_pack.odin

@@ -1,6 +1,6 @@
 package stb_rect_pack
 
-import c "core:c/libc"
+import c "core:c"
 
 #assert(size_of(b32) == size_of(c.int))
 
@@ -111,4 +111,4 @@ foreign lib {
 	// heuristics will produce better/worse results for different data sets.
 	// If you call init again, this will be reset to the default.
 	setup_heuristic :: proc(ctx: ^Context, heuristic: Heuristic) ---
-}
+}