Use gcc/sections/elf_shared.d on Solaris 11.5 (PR d/88150)

Use gcc/sections/elf_shared.d on Solaris 11.5 (PR d/88150)

	PR d/88150
	* libdruntime/gcc/sections/elf_shared.d [Solaris] (SharedELF): Set
	to true.
	Import core.sys.solaris.dlfcn, core.sys.solaris.link,
	core.sys.solaris.sys.elf, core.sys.solaris.sys.link.
	(dummy_ref): Declare.
	(initSections): Initialize dummy_ref.
	(getDependencies): Set strtab.
	(handleForName): Don't dlclose handle.
	(findDSOInfoForAddr): Set IterateManually.
	(getprogname): Declare.
	(progname): Use it.
	* libdruntime/gcc/sections/package.d [Solaris]: Import
	gcc.sections.elf_shared instead of gcc.sections.solaris.
	* libdruntime/gcc/sections/solaris.d: Remove.
	* libdruntime/Makefile.am (DRUNTIME_DSOURCES): Remove
	gcc/sections/solaris.d.

From-SVN: r270345