abuild: bugfix. allow apkbiudls without build()

abuild.in

@@ -292,7 +292,7 @@ runpart() {
 
 # override those in your build script
 build() {
-	die "No build() function found in $APKBUILD"
+	:
 }
 
 get_split_func() {
@@ -630,7 +630,7 @@ rootpkg() {
 	if is_function package; then
 		msg "Building without fakeroot"
 		build || return 1
-		do_build=
+		do_build=package
 	fi
 	cd "$startdir"
 	msg "Entering fakeroot..."