m4 has a field day parsing escapes and actually vandalizes this string,
causing the error to look like:
==> ERROR: \PKGBUILD\ not found or is not a file
Avoid all quoting and just match up with how makepkg reports errors (no
quoting at all).
Signed-off-by: Dave Reisner <dreisner@archlinux.org>
Signed-off-by: Dan McGee <dan@archlinux.org>