replacement for getsrcs.sh which now generates too much text to put on a
Linux command line. The approach taken with llvmgrep is to execute a find
command and execute a grep on each file that matches the name pattern. The
arguments to this script are the same as those of egrep. Note that the -H
and -n options to egrep will always be passed so that you always get the
file and line number of matches.

llvm-svn: 14255