While compiling stb_image's implementation on Fedora, the compiler cannot find the __builtin_cpu_supports intrinsic and gives a compilation error in the function stbi__sse2_available(). The workaround to this is to just remove the intrinsic call and return a 0.

Unfortunately, I won't be able to tell you the exact version of Fedora or gcc or libc, since the machine isn't available to me any more. I was compiling in 64 bit mode.

This is potentially related to issue #280.