Fix profile name files without -fprofile-dir.

2019-12-05  Martin Liska  <mliska@suse.cz>

	PR gcov-profile/91971
	* coverage.c (coverage_init): Mangle full path
	only when -fprofile-dir is used.

From-SVN: r278990

gcc/ChangeLog

+2019-12-05  Martin Liska  <mliska@suse.cz>
+
+	PR gcov-profile/91971
+	* coverage.c (coverage_init): Mangle full path
+	only when -fprofile-dir is used.
+
 2019-12-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/92791

gcc/coverage.c

@@ -1228,7 +1228,7 @@ coverage_init (const char *filename)
       else
 	profile_data_prefix = getpwd ();
     }
-  else
+  else if (profile_data_prefix != NULL)
     {
       /* when filename is a absolute path, we also need to mangle the full
       path of filename to prevent the profiling data being stored into a