STBIR-NO-UNROLL_LOOP_STAR breaks mingw gcc compilation

[TianZerL]

Describe the bug
#1655 adds STBIR-NO-UNROLL_LOOP_STAR to stb_image_resize2.h, whitch breaks mingw gcc compilation.

/stb_image_resize2.h: In function 'void stbir_simd_memcpy(void*, const void*, size_t)':
/stb_image_resize2.h:2588:12: error: missing loop condition in loop with 'GCC unroll' pragma before ';' token
 2588 |       for(;;)
      |   

To Reproduce
Steps to reproduce the behavior:
Use MinGW-W64 (14.1.0 for me) to build stb_image_resize2.h will get this error.

[yangfl]

Also on GCC 13/14.

Sample: https://godbolt.org/z/d9jvrxKfK

[jeffrbig2]

This was tested on GCC at compiler explorer, but I only have mingw my computer in another state. Maybe @TianZerL can check it?

[TianZerL]

@jeffrbig2
I can confirm that #1671 has fixed this for mingw gcc.
But I think there is still issue for clang: https://godbolt.org/z/dv6Tjadrf. Both mingw clang and x86 clang have the same issue.

[jeffrbig2]

Clang uses completely different pragmas?

[TianZerL]

@jeffrbig2
No, it should be compatible with gcc, but not completely compatible.
According to llvm/llvm-project#88624, it should have fixed in some versions, but not for Clang 18 in godbolt.
Maybe make _Pragma("GCC unroll 0") for gcc only?

[jeffrbig2]

Dude, what are you talking about? stb_image_resize2 has a separate clang codepath - it doesn't use the gcc pragmas at all?

Maybe make _Pragma("GCC unroll 0") for gcc only?

It is only for GCC!

[jeffrbig2]

Look at line 1206-1235...

[TianZerL]

@jeffrbig2
oops, my bad.

Clang uses completely different pragmas?

I thought this was a question 😂.

[jeffrbig2]

Haha, ok, cool!!

[nothings]

Fix committed.