From: Heiko Lewin <heiko.lewin@worldiety.de>
Date: Fri, 22 May 2020 03:32:33 +0200
Subject: configure: use LIBTOOL variable for Darwin builds

---
 configure |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/configure
+++ b/configure
@@ -69,6 +69,12 @@
 else
     NM=${NM-"nm"}
 fi
+if "${CROSS_PREFIX}libtool" --version >/dev/null 2>/dev/null || test $? -lt 126; then
+    LIBTOOL=${LIBTOOL-"${CROSS_PREFIX}libtool"}
+    test -n "${CROSS_PREFIX}" && echo Using ${LIBTOOL} | tee -a configure.log
+else
+    LIBTOOL=${LIBTOOL-"libtool"}
+fi
 
 # set defaults before processing command line options
 LDCONFIG=${LDCONFIG-"ldconfig"}
@@ -260,8 +266,8 @@
         SHAREDLIBV=libz.$VER$shared_ext
         SHAREDLIBM=libz.$VER1$shared_ext
         LDSHARED=${LDSHARED-"$cc -dynamiclib -install_name $libdir/$SHAREDLIBM -compatibility_version $VER1 -current_version $VER3"}
-        if libtool -V 2>&1 | grep Apple > /dev/null; then
-            AR="libtool"
+        if ${LIBTOOL} -V 2>&1 | grep Apple > /dev/null; then
+            AR="${LIBTOOL}"
         else
             AR="/usr/bin/libtool"
         fi