ktorrent: fix build w/ newer ECM

The FindTaglibc.cmake of ECM variable names differ from the one
which is shipped with ktorrent. Use the former.

srcpkgs/ktorrent/template

@@ -20,3 +20,8 @@ if [ "$CROSS_BUILD" ]; then
 	configure_args+=" -DDESKTOPTOJSON_EXECUTABLE=/usr/bin/desktoptojson"
 	hostmakedepends+=" kdoctools kconfig kcoreaddons"
 fi
+
+pre_configure() {
+	# The ECM FindTaglib.cmake gives different variable names
+	grep -rl TAGLIB_ | xargs -n1 sed -i -e "s;TAGLIB_;Taglib_;g"
+}