Use -fno-merge-debug-string to comply with Darwin
	* g++.dg/debug/dwarf2/namespace-1.C: Use -fno-merge-debug-string
	and adjust.
	* g++.dg/debug/dwarf2/template-func-params-6.C: Likewise.
	* g++.dg/debug/dwarf2/template-func-params-7.C: Likewise.
	* g++.dg/debug/dwarf2/template-params-6.C: Likewise.
	* g++.dg/debug/dwarf2/pubnames-1.C: Likewise. Also, adjust to
	take darwin specifics in account.

From-SVN: r151538