build: add arm64 support

Change-Id: I81e58c8fa88a871bcaa378f454884973bee0aff6
Tuleap: #1509
diff --git a/configure.sh b/configure.sh
index de7faaf..bcc6779 100755
--- a/configure.sh
+++ b/configure.sh
@@ -43,8 +43,8 @@
 CFLAGS="$CFLAGS ${RING_EXTRA_CFLAGS}" \
 CXXFLAGS="$CXXFLAGS ${RING_EXTRA_CXXFLAGS}" \
 LDFLAGS="$LDFLAGS ${RING_EXTRA_LDFLAGS}" \
-CC="clang" \
-CXX="clang++" \
+CC="${CROSS_COMPILE}clang" \
+CXX="${CROSS_COMPILE}clang++" \
 NM="${CROSS_COMPILE}nm" \
 STRIP="${CROSS_COMPILE}strip" \
 RANLIB="${CROSS_COMPILE}ranlib" \