add libs.cpp for header-only libs compilation unit

src/asset.cpp

@@ -2,9 +2,6 @@
 #include <cassert>
 #include <cstring>
 
-#define TINYGLTF_IMPLEMENTATION
-//#define STB_IMAGE_IMPLEMENTATION
-#define STB_IMAGE_WRITE_IMPLEMENTATION
 #include "tiny_gltf.h"
 
 #include "asset.h"

src/libs.cpp

@@ -0,0 +1,12 @@
+
+// NOTE: put all the header-only libs in a separate compilation unit to save on
+// 	compile times
+
+#define TINYGLTF_IMPLEMENTATION
+#include "tiny_gltf.h"
+
+#define STB_IMAGE_IMPLEMENTATION
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include "stb_image.h"
+#include "stb_image_write.h"
+

src/util_image.cpp

@@ -1,7 +1,6 @@
 
 #include <cstring>
 
-#define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"
 
 #include "dumbLog.h"