nvtx: support libc without char8_t

[cwsmith]

This PR addresses a compilation issue with the nvtx package with the python bindings enabled (as a dep of py-torch) when built with GCC 15.2.0 and glibc 2.34 on a RHEL9 system. IIUC, glibc 2.36 or newer is needed to use char8_t from the c20 standard (https://lists.gnu.org/archive/html/info-gnu/2022-08/msg00000.html).

A PR to the nvtx repo is here: NVIDIA/NVTX#163

On our system, the following code reproduces the bug:

$ cat foo.c 
#include <stdio.h> 
//---- uncomment the following block to compile ----
//#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
//#ifndef __cpp_char8_t
//typedef unsigned char char8_t;
//#endif
//#endif
int main() { char8_t a; printf("%ld\n", (long)__STDC_VERSION__); return 0; }

$ gcc --version
gcc (Spack GCC) 15.2.0
Copyright (C) 2025 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

##  show glibc version
$ ldd --version   
ldd (GNU libc) 2.34
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.

$ gcc foo.c -o foo
foo.c: In function 'main':
foo.c:9:14: error: unknown type name 'char8_t'; did you mean 'char'?
    9 | int main() { char8_t a; printf("%ld\n", (long)__STDC_VERSION__); return 0; }
      |              ^~~~~~~
      |              char

[thomas-bouvier]

LGTM, thanks for your contribution.

[becker33]

It looks like this is trying to build python components even when ~python.

I think it's missing a conditional around the pip call for whether python is enabled.

[sethrj]

@becker33 Shouldn't this be using the .patch file from the GitHub PR rather than a file filter?