diff --git a/sflphone-client-gnome/configure.ac b/sflphone-client-gnome/configure.ac
index 1faa55dc8f89b6dc5660e7b3acc663f6ae1f359b..ed4dbaeb59b348d991f02a3b55f3242379ff33b9 100644
--- a/sflphone-client-gnome/configure.ac
+++ b/sflphone-client-gnome/configure.ac
@@ -18,9 +18,9 @@ AC_ARG_WITH(debug,
 		[with_debug=no]
 	)
 if test "x$with_debug" = "xfull" -o "x$with_debug" = "xyes"; then
-	CFLAGS="$CFLAGS -g -O2 -DDEBUG -Wall -Wextra"
+	CFLAGS="-g -O0 -DDEBUG -Wall -Wextra"
 else
-	CFLAGS="$CFLAGS -g -Wall -O2"
+	CFLAGS="$CFLAGS"
 fi
 
 AC_PROG_CC
diff --git a/sflphone-common/configure.ac b/sflphone-common/configure.ac
index 103fb42273dd4687dee9341089e4ed8c0752aacd..cc0851b941e1901b65c9f77833322145e5156854 100644
--- a/sflphone-common/configure.ac
+++ b/sflphone-common/configure.ac
@@ -96,7 +96,8 @@ dnl Define C++ as default language
 AC_LANG(C++)
 
 dnl Setup C++ compiler flags
-CXXFLAGS="$CXXFLAGS $USE_EXCEPTIONS $USER_INCLUDES -O0 -g -Wno-return-type"
+CXXFLAGS="$CXXFLAGS $USE_EXCEPTIONS $USER_INCLUDES -g -Wno-return-type"
+dnl CXXFLAGS="$USE_EXCEPTIONS $USER_INCLUDES -O0 -g -Wno-return-type"
 
 dnl Check for header files
 AC_FUNC_ALLOCA
diff --git a/tools/build-system/distributions/mandriva/sflphone-common.spec b/tools/build-system/distributions/mandriva/sflphone-common.spec
index 11921a1d76bc92257bd4c53f44c54606aae8debd..fd29c286f5cbc0847291e4c8a17cabc99659cb3e 100644
--- a/tools/build-system/distributions/mandriva/sflphone-common.spec
+++ b/tools/build-system/distributions/mandriva/sflphone-common.spec
@@ -65,7 +65,7 @@ make dep
 make clean
 make
 cd -
-./autogen.sh --prefix=%{_prefix}
+./autogen.sh --prefix=%{_prefix} CXXFLAGS=-O2
 make -j
 
 %install
diff --git a/tools/build-system/distributions/opensuse/sflphone-common.spec b/tools/build-system/distributions/opensuse/sflphone-common.spec
index cb92f42505eb4a687576a840ece4ffaf45ffdc97..662db2a52b49624e640ed16b63a31011d7fe2e7b 100644
--- a/tools/build-system/distributions/opensuse/sflphone-common.spec
+++ b/tools/build-system/distributions/opensuse/sflphone-common.spec
@@ -64,7 +64,7 @@ make dep
 make clean
 make
 cd -
-./autogen.sh --prefix=%{_prefix}
+./autogen.sh --prefix=%{_prefix} CXXFLAGS=-O2
 make -j
 
 %install
diff --git a/tools/build-system/distributions/ubuntu/debian-sflphone-common/rules b/tools/build-system/distributions/ubuntu/debian-sflphone-common/rules
index d7235ece2b796b4f95933ac297042bd87a12058f..2c3de83130e77cc7cfda48e69e976a2b9dd28098 100755
--- a/tools/build-system/distributions/ubuntu/debian-sflphone-common/rules
+++ b/tools/build-system/distributions/ubuntu/debian-sflphone-common/rules
@@ -20,7 +20,7 @@ configure: configure-stamp
 configure-stamp:
 	dh_testdir
 	# Add here commands to configure the package.
-	./autogen.sh --prefix=/usr
+	./autogen.sh --prefix=/usr CXXFLAGS=O2
 	cd libs/pjproject-1.0.2; ./autogen.sh --prefix=/usr
 	touch configure-stamp