diff --git a/rtaudio.pc.in b/rtaudio.pc.in
index ea23395..0e81090 100644
--- a/rtaudio.pc.in
+++ b/rtaudio.pc.in
@@ -9,4 +9,4 @@ Version: @PACKAGE_VERSION@
 Requires: @req@ 
 Libs: -L${libdir} -lrtaudio
 Libs.private: -lpthread
-Cflags: -pthread -I${includedir}
+Cflags: -pthread -I${includedir} @api@