* configure.ac: Use ACX_PROG_LD_GNU_SYMBOLIC. Set
LIBGCJ_LD_SYMBOLIC_FUNCTIONS to $SYMBOLIC_LDFLAGS. Set
libgcj_ld_symbolic to $SYMBOLIC_LDFLAGS if it isn't set.
Substitute LIBGCJ_LD_SYMBOLIC_FUNCTIONS.
* configure: Regenerated.
* aclocal.m4: Likewise.
* gcj/Makefile.in: Likewise.
* include/Makefile.in: Likewise.
* testsuite/Makefile.in: Likewise.