We compile gcrt1.o with -fPIC to support both "gcc -pg" and "gcc -pie -pg".
[BZ #17836]
* csu/Makefile (extra-objs): Add gmon-start.o if not builing
shared library. Add gmon-start.os otherwise.
($(objpfx)g$(start-installed-name)): Use $(objpfx)S%
$(objpfx)gmon-start.os if builing shared library.
($(objpfx)g$(static-start-installed-name)): Likewise.