gdb/

gdb/
	PR symtab/13277: Resolving opaque structures in ICC generated binaries.
	* dwarf2read.c (struct dwarf2_cu) <producer_is_icc>: New field.
	(producer_is_gxx_lt_4_6): Move the checking and caching to...
	(check_producer): ... this new function, which also checks for ICC
	and caches the result.
	(producer_is_icc): New function.
	(read_structure_type): Don't set TYPE_STUB_SUPPORTED if the
	producer was ICC.

gdb/testsuite/
	PR symtab/13277: Resolving opaque structures in ICC generated binaries.
	* gdb.dwarf2/dw2-icc-opaque.S: New file.
	* gdb.dwarf2/dw2-icc-opaque.exp: New file.