[Bug fortran/71839] undefined reference to `_gfortran_caf_stop_str'

["mexas at bristol dot ac.uk" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71839

--- Comment #3 from Anton Shterenlikht <mexas at bristol dot ac.uk> ---
In the end I reduced the program to:

use cgca
if (.true.) stop
end

The problem seems to appear if I move the
static library from where it was built to another location.

E.g if I build my library, and the program, in some directory,
then all is fine:

$ ls libcgpack.a
libcgpack.a
$ caf -c z.f90 -I .
$ caf z.o -L . -lcgpack
$ ./a.out 
STOP 

However, if I move the library to another place, then I get this error:

$ cp libcgpack.a ~/lib/
$ caf z.o -L ~/lib/ -lcgpack
z.o: In function `MAIN__':
z.f90:(.text+0xf): undefined reference to `_gfortran_caf_stop_str'
collect2: error: ld returned 1 exit status

Does this look like a binutils problem?
Or am I making some mistake in creating the library?