#170 lcov ignores symlinked .c files

[David Edell]

lcov provides an option to follow symlinks for .da files, but not for source files.

In my case, I've got symlinks to C files cherry-picked from several different directories. It was simpler to create symlinks than to construct a complex Makefile that picks some source files from their original location, and overrides others for test purposes. All of my .gcda and .gcno files are in one directory along with my .c files. lcov parses all files local to that directory without issue, but skips those .c files that are actually symlinks.