re: lib/60324: unwind.h build race condition

The following reply was made to PR lib/60324; it has been noted by GNATS.

From: matthew green <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], [email protected], [email protected]
Subject: re: lib/60324: unwind.h build race condition
Date: Thu, 09 Jul 2026 11:11:26 +1000

 sorry, i'd missed this PR being submitted.
 
 i think the fix you commited is fine, and nicely found on what
 is likely going wrong (i'm convinced by your analysis.)
 
 
 maybe the real fix is to not enter this subdirectory twice in
 this same high-level .WAIT group at all.
 
 there are a few subdirs we traverse twice but perhaps we should
 stop doing that entirely.  eg, src/Makefile had (the first line
 would have a .WAIT now):
 
 _SUBDIR=3D        tools .WAIT lib
 _SUBDIR+=3D       include external crypto/external bin
 
 and src/external/Makefile has:
 
 SUBDIR+=3D amdgpu-firmware apache2 atheros broadcom bsd cddl gpl2 gpl3 his=
 torical
 
 and src/external/gpl3/Makefile has:
 
 SUBDIR+=3D        ${EXTERNAL_GCC_SUBDIR}
 
 etc., where it ends up entering libgcc from multiple parts of
 the same .WAIT segment.
 
 this isn't the only one, but maybe it's the only one that has
 a build-a-file conflict.  not doing this would mean we could
 take the new .WAIT away again.
 
 it might be nice to still allow this with some variable set,
 since eg, i will cleandir in src/external/gpl3/gcc and rebuild
 just that sometimes when i'm testing gcc stuff, but i'm fine
 for this to be a special thing you have to ask for.)
 
 
 thanks.
 
 
 .mrg.