I have been able to reliable reproduce the build race, using make -j > 1. the following will trigger the build failure.
the proposed patch in message 10 is incomplete. testbreakcompile.patch --- a/Makefile.in 2023-07-12 13:55:26.000000000 +0000 +++ b/Makefile.in 2023-07-22 05:00:09.718180145 +0000 @@ -1163,7 +1163,7 @@ @MACOSX_TRUE@wrapped.h wrapdef.h wrapstruct.h wraptmpf.h:wrapawk_macosx wrapfunc.inp @MACOSX_TRUE@ awk -f $(srcdir)/wrapawk_macosx < $(srcdir)/wrapfunc.inp @MACOSX_FALSE@wrapped.h wrapdef.h wrapstruct.h wraptmpf.h:wrapawk wrapfunc.inp -@MACOSX_FALSE@ awk -f $(srcdir)/wrapawk < $(srcdir)/wrapfunc.inp +@MACOSX_FALSE@ sleep 100;awk -f $(srcdir)/wrapawk < $(srcdir)/wrapfunc.inp libfakeroot.lo:libfakeroot.c wrapdef.h wrapstruct.h wraptmpf.h --- a/Makefile.am 2023-07-22 04:59:30.671246641 +0000 +++ b/Makefile.am 2023-07-22 05:01:52.345546358 +0000 @@ -52,7 +52,7 @@ awk -f $(srcdir)/wrapawk_macosx < $(srcdir)/wrapfunc.inp else !MACOSX wrapped.h wrapdef.h wrapstruct.h wraptmpf.h:wrapawk wrapfunc.inp - awk -f $(srcdir)/wrapawk < $(srcdir)/wrapfunc.inp + sleep 100; awk -f $(srcdir)/wrapawk < $(srcdir)/wrapfunc.inp endif !MACOSX libfakeroot.lo:libfakeroot.c wrapdef.h wrapstruct.h wraptmpf.h