diff --git a/libheif.pc.in b/libheif.pc.in
index ef7470ca1b..1057594da9 100644
--- a/libheif.pc.in
+++ b/libheif.pc.in
@@ -12,3 +12,4 @@ Requires.private: @REQUIRES_PRIVATE@
 Libs: -L${libdir} -lheif
 Libs.private: @LIBS_PRIVATE@
 Cflags: -I${includedir}
+Cflags.private: -DLIBHEIF_STATIC_BUILD