csync: fix gcc6 build

srcpkgs/csync/template

@@ -1,7 +1,7 @@
 # Template file for 'csync'
 pkgname=csync
 version=0.50.0
-revision=2
+revision=3
 build_style=cmake
 configure_args="-DSYSCONF_INSTALL_DIR=/etc"
 conf_files="/etc/csync/csync.conf /etc/csync/csync_exclude.conf"
@@ -14,6 +14,11 @@ homepage="http://csync.org"
 distfiles="http://git.csync.org/projects/csync.git/snapshot/csync-${version}.tar.bz2"
 checksum=72e95f6924ca01783afcfc9c68d416a50e0bec979cf4e1fc414df352210d6a0f
 
+pre_configure() {
+	sed -i cmake/Modules/DefineCompilerFlags.cmake \
+		-e's; -pedantic-errors;;'
+}
+
 post_build() {
 	cd ${wrksrc}/doc
 	./makeman.sh csync.1.txt