devel/electron*: Fix build on main

[jrm]

Summary

After src snapshot 0c47b9c211e, the build began failing with:

../../third_party/nasm/include/compiler.h:249:21: error: static
 declaration of 'mempcpy' follows non-static declaration
  249 | static inline void *mempcpy(void *dst, const void *src, size_t n)
      |                     ^
/usr/include/string.h:71:8: note: previous declaration is here
   71 | void    *(mempcpy)(void * __restrict, const void * __restrict, size_t);
      |           ^

Restore the default definition of HAVE_MEMPCPY as mempcpy() has been
available since 13.1, and remove a patch used to detect mempcpy() in
/usr/include/string.h, as it is no longer necessary and does not match
the function.

Test Plan

I'm still running build tests. Will update here soon.

[lwhsu]

Might be worth also send to https://github.com/tagattie/FreeBSD-Electron ?

[tagattie]

There is another proposed patch (for www/qt6-webengine) at https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=280376, which is also applicable to devel/electron*.

In addition to the changes to patch-third__party_nasm_config_config-linux.h, we should remove patch-third__party_nasm_BUILD.gn altogether. Those changes are remnants from the time when not all FreeBSD versions did not support mempcpy(3).

Can you update the changes accordingly?

Thanks,
Hiroki

[jrm]

Also remove patch-third__party_nasm_BUILD.gn.

[tagattie]

Looks good to me. Thank you!