Disable frame pointer elimination when using -pg
(Re-apply patch after bug fixing)
This diff makes sure that the driver does not pass
-fomit-frame-pointer or -momit-leaf-frame-pointer to
the frontend when -pg is used. Currently, clang gives
an error if -fomit-frame-pointer is used in combination
with -pg, but -momit-leaf-frame-pointer was forgotten.
Also, disable frame pointer elimination in the frontend
when -pg is set.
Patch by Stefan Kempf.