Reviewed possible issue with external libs

src/Makefile

@@ -342,9 +342,6 @@ endif
 INCLUDE_PATHS = -I. -Iexternal/glfw/include
 
 ifeq ($(PLATFORM),PLATFORM_DESKTOP)
-    ifeq ($(PLATFORM_OS),WINDOWS)
-        INCLUDE_PATHS += -Iexternal
-    endif
     ifeq ($(PLATFORM_OS),BSD)
         INCLUDE_PATHS += -I/usr/local/include
         LDFLAGS += -L. -Lsrc -L/usr/local/lib -L$(RAYLIB_RELEASE_PATH)

src/core.c

@@ -125,7 +125,7 @@
 #include <ctype.h>          // Required for: tolower() [Used in IsFileExtension()]
 #include <sys/stat.h>       // Required for stat() [Used in GetLastWriteTime()]
 
-#if defined(_WIN32) && defined(_MSC_VER)
+#if defined(PLATFORM_DESKTOP) && defined(_WIN32) && defined(_MSC_VER)
     #include "external/dirent.h"    // Required for: DIR, opendir(), closedir() [Used in GetDirectoryFiles()]
 #else
     #include <dirent.h>             // Required for: DIR, opendir(), closedir() [Used in GetDirectoryFiles()]