Improve support for web building

Note that building examples for web as they are (no code adaptation for web avoiding while loop) implies using the emterpreter... and that's very slow!

examples/Makefile

@@ -117,9 +117,9 @@ endif
 
 ifeq ($(PLATFORM),PLATFORM_WEB)
     # Emscripten required variables
-    EMSDK_PATH          = C:/emsdk
-    EMSCRIPTEN_VERSION  = 1.38.30
-    CLANG_VERSION       = e1.38.30_64bit
+    EMSDK_PATH          ?= D:/emsdk
+    EMSCRIPTEN_VERSION  ?= 1.38.31
+    CLANG_VERSION       = e$(EMSCRIPTEN_VERSION)_64bit
     PYTHON_VERSION      = 2.7.13.1_64bit\python-2.7.13.amd64
     NODE_VERSION        = 8.9.1_64bit
     export PATH         = $(EMSDK_PATH);$(EMSDK_PATH)\clang\$(CLANG_VERSION);$(EMSDK_PATH)\node\$(NODE_VERSION)\bin;$(EMSDK_PATH)\python\$(PYTHON_VERSION);$(EMSDK_PATH)\emscripten\$(EMSCRIPTEN_VERSION);C:\raylib\MinGW\bin:$$(PATH)
@@ -249,8 +249,7 @@ ifeq ($(PLATFORM),PLATFORM_WEB)
     # -s FORCE_FILESYSTEM=1      # force filesystem to load/save files data
     # --profiling                # include information for code profiling
     # --preload-file resources   # specify a resources folder for data compilation
-    CFLAGS += -Os -s USE_GLFW=3 -s ASSERTIONS=2 -s WASM=1 -s FORCE_FILESYSTEM=1
-    # -s EMTERPRETIFY=1 -s EMTERPRETIFY_ASYNC=1 --preload-file audio/resources@resources
+    CFLAGS += -Os -s USE_GLFW=3 -s ASSERTIONS=2 -s WASM=1 -s FORCE_FILESYSTEM=1 -s EMTERPRETIFY=1 -s EMTERPRETIFY_ASYNC=1 --preload-file $(dir $<)resources@resources
     
     # NOTE: Simple raylib examples are compiled to be interpreter by emterpreter, that way,
     # we can compile same code for ALL platforms with no change required, but, working on bigger