abuild: add a cross_compiling helper function

to detect if we cross compile

abuild.in

@@ -104,6 +104,10 @@ set_xterm_title() {
 	fi
 }
 
+cross_compiling() {
+	test "$CBUILD" != "$CHOST" -a -n "$CBUILDROOT"
+}
+
 cleanup() {
 	local i=
 	set_xterm_title ""
@@ -118,7 +122,7 @@ cleanup() {
 			if [ -z "$install_after" ] && [ -n "$uninstall_after" ]; then
 				msg "Uninstalling dependencies..."
 				$SUDO_APK del --quiet $apk_opt_wait $uninstall_after
-				if [ "$CBUILD" != "$CHOST" -a -n "$CBUILDROOT" ]; then
+				if cross_compiling; then
 					$SUDO_APK del --root "$CBUILDROOT" \
 						--quiet $apk_opt_wait \
 						$uninstall_after
@@ -996,7 +1000,7 @@ trace_apk_deps() {
 		# first check if its provided by same apkbuild
 		grep -q -w "^$i" "$dir"/.provides-so 2>/dev/null && continue
 
-		if subpkg_provides "$i" || [ "$CBUILD" != "$CHOST" ] \
+		if subpkg_provides "$i" || cross_compiling \
 				|| $APK info --quiet --installed "so:$i"; then
 			autodeps="$autodeps so:$i"
 		else
@@ -1531,7 +1535,7 @@ builddeps() {
 	msg "Analyzing dependencies..."
 
 	# add depends unless it is a subpackage or package itself
-	if [ "$CBUILD" != "$CHOST" -a -n "$CBUILDROOT" ] && [ -n "$makedepends_build" -o -n "$makedepends_host" ]; then
+	if cross_compiling && [ -n "$makedepends_build" -o -n "$makedepends_host" ]; then
 		for i in $BUILD_BASE $makedepends_build; do
 			[ "$pkgname" = "${i%%[<>=]*}" ] && continue
 			subpackages_has ${i%%[<>=]*} || builddeps="$builddeps $i"
@@ -1774,8 +1778,10 @@ deps() {
 
 undeps (){
 	$SUDO_APK del $apk_opt_wait .makedepends-$pkgname
-	[ "$CBUILD" != "$CHOST" -a -n "$CBUILDROOT" ] &&
-		$SUDO_APK del --root "$CBUILDROOT" $apk_opt_wait .makedepends-$pkgname
+	if cross_compiling; then
+		$SUDO_APK del --root "$CBUILDROOT" $apk_opt_wait \
+			.makedepends-$pkgname
+	fi
 }
 
 # compat