Support profiling PIE [BZ #22284]

Support profiling PIE [BZ #22284]

Since PIE can be loaded at any address, we need to subtract load address
from PCs.

	[BZ #22284]
	* gmon/Makefile [$(have-fpie)$(build-shared) == yesyes] (tests,
	tests-pie): Add tst-gmon-pie.
	(CFLAGS-tst-gmon-pie.c): New.
	(CRT-tst-gmon-pie): Likewise.
	(tst-gmon-pie-ENV): Likewise.
	[$(have-fpie)$(build-shared) == yesyes] (tests-special): Likewise.
	($(objpfx)tst-gmon-pie.out): Likewise.
	(clean-tst-gmon-pie-data): Likewise.
	($(objpfx)tst-gmon-pie-gprof.out): Likewise.
	* gmon/gmon.c [PIC]: Include <link.h>.
	[PIC] (callback): New function.
	(write_hist): Add an argument for load address.  Subtract load
	address from PCs.
	(write_call_graph): Likewise.
	(write_gmon): Call __dl_iterate_phdr to get load address, pass
	it to write_hist and write_call_graph.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>