As reported by Robert Scott in https://github.com/NixOS/nixpkgs/pull/245066
without the change `make -j8` build of `make` occasionally fails to
buildin parallel. The simplest reproducer is:
$$ ./configure
$$ make unwind_prot.o
...
In file included from unwind_prot.c:51:
In file included from ./bashintl.h:30:
./include/gettext.h:27:11: fatal error: 'libintl.h' file not found
# include <libintl.h>
^~~~~~~~~~~
1 error generated.
make: * [Makefile:106: unwind_prot.o] Error 1
The change adds missing ttransitive `${LIBINTL_H}` dependency for
unwind_prot.o.
