Look closer at those matches which gid "missed", and you will see why
it didn't show them to you.
I looked close (before you asked), and no, I don't see why some matches
are not included. For example it returns
lib/tempname.c:212: __GT_FILE: create the file using open(O_CREAT|O_EXCL)
but not
lib/tempname.h:47: GT_FILE: create a large file using open(O_CREAT|O_EXCL)
and it returns
lib/open.c:99: /* Fail if one of O_CREAT, O_WRONLY, O_RDWR is specified and the
filename
but not
lisp/gnus/nnmaildir.el:387: ;; If Emacs had O_CREAT|O_EXCL, we could return
number-open here.