Enable initfini array support on Solaris (PR target/50166)

Enable initfini array support on Solaris (PR target/50166)

	* acinclude.m4 (gcc_AC_INITFINI_ARRAY): Require gcc_SUN_LD_VERSION.
	Define _start.
	Remove -e 0 from $gcc_cv_ld invocation.
	Only use __GLIBC_PREREQ if defined.
	Enable on Solaris since Solaris 8 patch.
	(gcc_SUN_LD_VERSION): New macro.
	* configure.ac (ld_ver) <*-*-solaris2*>: Refer to
	gcc_SUN_LD_VERSION for version number format.
	* configure: Regenerate.
	* varasm.c (get_elf_initfini_array_priority_section): Set
	SECTION_NOTYPE for non-default priority.
	Use get_section instead of get_unnamed_section to emit
	.init_array/.fini_array with default priority.

From-SVN: r184390