wasm: support more vendor libraries

Adds support for:
- box2d
- cgltf
- stb image
- stb rect pack

vendor/stb/sprintf/stb_sprintf.odin

@@ -0,0 +1,37 @@
+package stb_sprintf
+
+import "core:c"
+
+@(private)
+LIB :: (
+	     "../lib/stb_sprintf.lib"      when ODIN_OS == .Windows
+	else "../lib/stb_sprintf.a"        when ODIN_OS == .Linux
+	else "../lib/darwin/stb_sprintf.a" when ODIN_OS == .Darwin
+	else "../lib/stb_sprintf_wasm.o"   when ODIN_ARCH == .wasm32 || ODIN_ARCH == .wasm64p32
+	else ""
+)
+
+when LIB != "" {
+	when !#exists(LIB) {
+		#panic("Could not find the compiled STB libraries, they can be compiled by running `make -C \"" + ODIN_ROOT + "vendor/stb/src\"`")
+	}
+}
+
+when ODIN_ARCH == .wasm32 || ODIN_ARCH == .wasm64p32 {
+	foreign import stbpf "../lib/stb_sprintf_wasm.o"
+} else when LIB != "" {
+	foreign import stbpf { LIB }
+} else {
+	foreign import stbpf "system:stb_sprintf"
+}
+
+@(link_prefix="stbsp_", default_calling_convention="c")
+foreign stbpf {
+	sprintf    :: proc(buf: [^]byte, fmt: cstring, #c_vararg args: ..any) -> i32 ---
+	snprintf   :: proc(buf: [^]byte, count: i32, fmt: cstring, #c_vararg args: ..any) -> i32 ---
+	vsprintf   :: proc(buf: [^]byte, fmt: cstring, va: c.va_list) -> i32 ---
+	vsnprintf  :: proc(buf: [^]byte, count: i32, fmt: cstring, va: ^c.va_list) -> i32 ---
+	vsprintfcb :: proc(callback: SPRINTFCB, user: rawptr, buf: [^]byte, fmt: cstring, va: ^c.va_list) -> i32 ---
+}
+
+SPRINTFCB :: #type proc "c" (buf: [^]byte, user: rawptr, len: i32) -> cstring