diff --git a/src/libuev.pc.in b/src/libuev.pc.in
index 9f831a6..4b00176 100644
--- a/src/libuev.pc.in
+++ b/src/libuev.pc.in
@@ -8,5 +8,5 @@ Description: Simple event loop for Linux
 Version: @VERSION@
 Requires:
 Libs: -L${libdir} -luev
-Cflags: -I${includedir}
+Cflags: -I${includedir} -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64