re PR gcov-profile/86957 (gcc should warn about missing profiles for a compilation unit or a new function with -fprofile-use)

2018-09-26  Indu Bhagat  <indu.bhagat@oracle.com>

	PR gcov-profile/86957
	* common.opt: New warning option -Wmissing-profile.
	* coverage.c (get_coverage_counts): Add warning for missing .gcda file.
	* doc/invoke.texi: Document -Wmissing-profile.

From-SVN: r264657