diff --git a/ksquirrellibs.pc.in b/ksquirrellibs.pc.in
index 3c8ac20..f10767d 100644
--- a/ksquirrellibs.pc.in
+++ b/ksquirrellibs.pc.in
@@ -8,4 +8,4 @@ Name: ksquirrellibs
 Description: Image codecs for KSquirrel
 Version: @VERSION@
 Libs: -L${libdir} -lksquirrel-libs
-Cflags: -I${includedir} -DSQ_KLIBS=\"${libdir}/ksquirrel-libs\" -DSQ_KL_VER=\"${version}\"
+Cflags: -I${includedir} -D'SQ_KLIBS=\"${libdir}/ksquirrel-libs\"' -D'SQ_KL_VER=\"${version}\"'