purge-distfiles: grep instead of sourcing template

To catch all SHA256 hashes from a template, even the ones which
are used only under certain preconditions, use grep [0-9a-f]{64} to
find all hashes in a template.

The may be some false positives which does not hurt the intended
purpose to purge obsolete distfiles.

Signed-off-by: Jürgen Buchmüller <pullmoll@t-online.de>

common/xbps-src/shutils/purge_distfiles.sh

@@ -4,10 +4,7 @@
 
 
 purge_distfiles() {
-	# Ignore msg_error calls when sourcing templates
-	msg_error() {
-		:
-	}
+	readonly HASHLEN=64
 	if [ -z "$XBPS_SRCDISTDIR" ]; then
 		msg_error "The variable \$XBPS_SRCDISTDIR is not set."
 		exit 1
@@ -28,8 +25,7 @@ purge_distfiles() {
 		pkg=${template#*/}
 		pkg=${pkg%/*}
 		if [ ! -L "srcpkgs/$pkg" ]; then
-			unset checksum
-			source $template 2>/dev/null
+			checksum="$(grep -Ehrow [0-9a-f]{$HASHLEN} ${template}|sort|uniq)"
 			read -a _my_hashes <<< ${checksum}
 			i=0
 			while [ -n "${_my_hashes[$i]}" ]; do
@@ -77,7 +73,6 @@ purge_distfiles() {
 	echo
 
 	hashes=($XBPS_SRCDISTDIR/by_sha256/*)
-	readonly HASHLEN=64
 	for file in ${hashes[@]}; do
 		hash_distfile=${file##*/}
 		hash=${hash_distfile:0:$HASHLEN}