abuild: set CTARGET_ARCH and CTARGET_LIBC

For better crosscompile support

abuild.in

@@ -1813,6 +1813,25 @@ snapshot() {
                 fi
 }
 
+hostspec_to_arch() {
+	case "$1" in
+	arm*-*-*-*eabi)		echo "armel" ;;
+	arm*-*-*-*eabihf)	echo "armhf" ;;
+	i[0-9]86-*-*-*)		echo "x86" ;;
+	x86_64-*-*-*)		echo "x86_64" ;;
+	*)			echo "unknown" ;;
+	esac
+}
+
+hostspec_to_libc() {
+	case "$1" in
+	*-*-*-uclibc*)	echo "uclibc" ;;
+	*-*-*-musl*)	echo "musl" ;;
+	*-*-*-gnu*)	echo "eglibc" ;;
+	*)		echo "uclibc" ;;
+	esac
+}
+
 usage() {
 	echo "$program $abuild_ver"
 	echo "usage: $program [options] [-i PKG] [-P REPODEST] [-p PKGDEST]"
@@ -1907,25 +1926,12 @@ repo=${repo##*/}
 SRCDEST=${SRCDEST:-$startdir}
 PKGDEST=${PKGDEST:-$startdir}
 
-if [ -z "$CARCH" ]; then
-	case "$CHOST" in
-	arm*-*-*-*)	CARCH="armel" ;;
-	i[0-9]86-*-*-*)	CARCH="x86" ;;
-	x86_64-*-*-*)	CARCH="x86_64" ;;
-	esac
-fi
-
-if [ -z "$CLIBC" ]; then
-	case "$CHOST" in
-	*-*-*-uclibc*)	CLIBC="uclibc" ;;
-	*-*-*-musl*)	CLIBC="musl" ;;
-	*-*-*-gnu*)	CLIBC="eglibc" ;;
-	*)		CLIBC="uclibc" ;;
-	esac
-fi
-
 [ -z "$CBUILD" ] && CBUILD="$CHOST"
 [ -z "$CTARGET" ] && CTARGET="$CHOST"
+[ -z "$CARCH" ] && CARCH="$(hostspec_to_arch $CHOST)"
+[ -z "$CLIBC" ] && CLIBC="$(hostspec_to_libc $CHOST)"
+[ -z "$CTARGET_ARCH" ] && CTARGET_ARCH="$(hostspec_to_arch $CTARGET)"
+[ -z "$CTARGET_LIBC" ] && CTARGET_LIBC="$(hostspec_to_libc $CTARGET)"
 
 # set a default CC
 : ${CC:=gcc}