diff --git a/linphone/Makefile.am b/linphone/Makefile.am
index 74d2b79e6..34353eeea 100644
--- a/linphone/Makefile.am
+++ b/linphone/Makefile.am
@@ -1,7 +1,7 @@
 ## Process this file with automake to produce Makefile.in
 
 # let make re-run automake upon need
-ACLOCAL_AMFLAGS = -I m4 -I/opt/local/share/aclocal
+ACLOCAL_AMFLAGS = -I m4 $(ACLOCAL_MACOS_FLAGS)
 
 if EXTERNAL_ORTP
 ORTP_DIR =
diff --git a/linphone/configure.in b/linphone/configure.in
index 63489b507..3e708c1aa 100644
--- a/linphone/configure.in
+++ b/linphone/configure.in
@@ -1,6 +1,6 @@
 dnl Process this file with autoconf to produce a configure script.
 
-AC_INIT([linphone],[3.1.2],[linphone-developers@nongnu.org])
+AC_INIT([linphone],[3.1.99.0],[linphone-developers@nongnu.org])
 AC_CANONICAL_SYSTEM
 
 dnl Source packaging numbers
@@ -41,8 +41,13 @@ case $target_os in
 		CONSOLE_FLAGS="-mconsole"
 		mingw_found=yes
 	;;
+	*darwin*)
+		dnl use macport installation
+		ACLOCAL_MACOS_FLAGS="-I /opt/local/share/aclocal"
+	;;
 esac
 
+AC_SUBST(ACLOCAL_MACOS_FLAGS)
 AC_SUBST(CONSOLE_FLAGS)
 AC_SUBST(GUI_FLAGS)