Run vismain only if linker supports protected data symbol

Run vismain only if linker supports protected data symbol

Gold doesn't support protected data symbol:

configure:5672: checking linker support for protected data symbol
configure:5682: gcc -fuse-ld=gold -nostdlib -nostartfiles -fno-stack-protector -fPIC -shared conftest.c -o conftest.so
configure:5685: $? = 0
configure:5692: gcc -fuse-ld=gold -nostdlib -nostartfiles -fno-stack-protector conftest.c -o conftest conftest.so
/usr/local/bin/ld.gold: error: /tmp/ccXWoofs.o: cannot make copy relocation for protected symbol 'bar', defined in conftest.so
collect2: error: ld returned 1 exit status

Run vismain only if linker supports protected data symbol.

	* elf/Makefile (tests): Add vismain only if
	$(have-protected-data) == yes.
	(tests-pie): Likewise.