abuild: support for variable options

so far only option avaiable is !strip, which disables stripping of binaries.

abuild

@@ -315,7 +315,7 @@ EOF
 }
 
 package() {
-	stripbin
+	options_has "!strip" ||	stripbin
 	package_apk
 }
 
@@ -558,6 +558,21 @@ subpackages_has() {
 	return 1
 }
 
+list_has() {
+	local needle="$1"
+	local i
+	shift
+	for i in $@; do
+		[ "$needle" = "$i" ] && return 0
+		[ "$needle" = "!$i" ] && return 1
+	done
+	return 1
+}
+
+options_has() {
+	list_has "$1" $options
+}
+
 # install package after build
 post_add() {
 	local pkgf="$PKGDEST/$1-$pkgver-r$pkgrel.apk"