Fix tcc not finding emmintrin.h (#1947)

* Fix tcc not finding emmintrin.h

This allows to compile raylib with tcc with no errors.

* Remove __TINYC__ check from stb_image.h

This will be placed under textures.c

* Move tcc check to textures.c

Avoiding to change stb_image.h

src/textures.c

@@ -102,6 +102,10 @@
 #define STBI_NO_PIC
 #define STBI_NO_PNM             // Image format .ppm and .pgm
 
+#if defined(__TINYC__)
+    #define STBI_NO_SIMD
+#endif
+
 #if (defined(SUPPORT_FILEFORMAT_BMP) || \
      defined(SUPPORT_FILEFORMAT_PNG) || \
      defined(SUPPORT_FILEFORMAT_TGA) || \