Have 'dlopen' use RTLD_GLOBAL in 'dynlib_open'

Have 'dlopen' use RTLD_GLOBAL in 'dynlib_open'

* src/pdumper.c (dump_do_dump_relocation): Use 'dynlib_open_for_eln'
in place of 'dynlib_open'.
* src/dynlib.h (dynlib_open_for_eln): Declare it.
* src/dynlib.c (dynlib_open_for_eln): New function.
(dynlib_open): Add RTLD_GLOBAL.
* src/comp.c (Fnative_elisp_load): Use 'dynlib_open_for_eln' in place
of 'dynlib_open'.