diff -ur cfitsio-4.0.0/cfitsio.pc.in cfitsio-4.0.0.pc/cfitsio.pc.in
--- cfitsio-4.0.0/cfitsio.pc.in	2021-05-20 03:18:54.000000000 +0200
+++ cfitsio-4.0.0.pc/cfitsio.pc.in	2021-12-03 17:38:32.302407819 +0100
@@ -1,7 +1,7 @@
 prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
-includedir=@includedir@
+includedir=@includedir@/cfitsio
 
 Name: cfitsio
 Description: FITS File Subroutine Library