Provide __start_minfo/__stop_minfo for linkers that don't (PR d/87864)

Provide __start_minfo/__stop_minfo for linkers that don't (PR d/87864)

	libphobos:
	PR d/87864
	* configure.ac (DRTSTUFF_SPEC): New variable.
	Substitute it.
	* libdruntime/m4/druntime/os.m4 (DRUNTIME_OS_MINFO_BRACKETING):
	New automake conditional.
	* configure: Regenerate.
	* libdruntime/gcc/drtstuff.c: New file.
	* libdruntime/Makefile.am [!DRUNTIME_OS_MINFO_BRACKETING]
	(DRTSTUFF, toolexeclib_DATA): New variables.
	(gcc/drtbegin.lo, gcc/drtend.lo): New rules.
	(libgdruntime_la_LDFLAGS): Use -Wc instead of -Xcompiler.
	Add -dstartfiles -B../src -Bgcc.
	(libgdruntime_la_DEPENDENCIES): New variable.
	(unittest_static_LDFLAGS): Use -Wc instead of -Xcompiler.
	(libgdruntime_t_la_LDFLAGS): Likewise.
	(unittest_LDFLAGS): Likewise.
	* src/Makefile.am (libgphobos_la_LDFLAGS): Use -Wc instead of
	-Xcompiler.
	Add -dstartfiles -B../libdruntime/gcc.
	(unittest_static_LDFLAGS): Use -Wc instead of -Xcompiler.
	(libgphobos_t_la_LDFLAGS): Likewise.
	(unittest_LDFLAGS): Likewise.
	* libdruntime/Makefile.in, src/Makefile.in: Regenerate.
	* Makefile.in, testsuite/Makefile.in: Regenerate.
	* libdruntime/rt/sections_elf_shared.d (Minfo_Bracketing): Don't
	assert.
	* libdruntime/gcc/config.d.in (Minfo_Bracketing): Remove.
	* src/drtstuff.spec: New file.
	* src/libgphobos.spec.in (DRTSTUFF_SPEC): Substitute.
	(*lib): Only pass SPEC_PHOBOS_DEPS without -debuglib, -defaultlib,
	-nophoboslib.
	* testsuite/testsuite_flags.in <--gdcldflags> (GDCLDFLAGS): Add
	-B${BUILD_DIR}/libdruntime/gcc.

	gcc/d:
	PR d/87864
	* lang.opt (dstartfiles): New option.
	* d-spec.cc (need_spec): New variable.
	(lang_specific_driver) <OPT_dstartfiles>: Enable need_spec.
	(lang_specific_pre_link): Also load libgphobos.spec if need_spec.

	gcc/testsuite:
	PR d/87864
	* lib/gdc.exp (gdc_link_flags): Add path to drtbegin.o/drtend.o if
	present.

From-SVN: r268886