blockcheck: check existense instead of curl

blockcheck.sh

@@ -482,7 +482,7 @@ check_prerequisites()
 		exitp 6
 	}
 
-	local prog progs='curl'
+	local prog progs="$CURL"
 	[ "$SKIP_PKTWS" = 1 ] || {
 		case "$UNAME" in
 			Linux)

common/base.sh

@@ -4,6 +4,10 @@ which()
 	# 'command -v' replacement does not work exactly the same way. it outputs shell aliases if present
 	# $1 - executable name
 	local IFS=:
+	[ "$1" != "${1#/}" ] && [ -x "$1" ] && {
+		echo "$1"
+		return 0
+	}
 	for p in $PATH; do
 	    [ -x "$p/$1" ] && {
 		echo "$p/$1"