ggml: fix ms compiler error involving restrict keyword

[grahameth]

Use __restrict instead of restrict on MS compiler to prevent compiler error on VS2017 and VS2019.

[slaren]

Can you help me understand what does this exactly enable? Isn't building with MSVC already supported? I can build without issue (well, other than the million of warnings) with VS 2019 Community.

[grahameth]

Hm, that's strange. I get this error on the first line where restrict is used:

ggml.h(889): error C2146: syntax error: missing ')' before identifier 'x'

I checked this on one computer with VS2017 and on another with VS2019

[slaren]

I am not sure in what version this was added, but MSVC does support restrict with /std:c11.

[grahameth]

Well, I updated my MSVC 2017 and also updated the language standard in the project settings, but I still get the same error. But if I'm the only one with this issue I guess you can close it.

[grencez]

@grahameth are you using CMake? If so, check the compile_commands.json file in the build directory to find the exact build command. Maybe it's not compiling ggml.c as C11 (or newer). C++ or older C versions won't recognize the keyword.

[Green-Sky]

afaik MS was very (very) slow to add c11 features to their compiler, so might just be a miss.
nvm, it's a c99 feature.

    C99 standard (ISO/IEC 9899:1999): 

        6.7.3.1 Formal definition of restrict (p: 110-112) 

[grahameth]

@grencez I don't find a generated file named "compile_commands.json" anywhere.

But anyway, I just set up a VM with a fresh install of VS2022 and cmake and there it indeed works. I still don't understand why it doesn't work on my machines, but it's not worth the time to investigate this.