diff --git a/config.h.cmake.in b/config.h.cmake.in
index bce755f..5f7a4c7 100644
--- a/config.h.cmake.in
+++ b/config.h.cmake.in
@@ -17,6 +17,7 @@
 #cmakedefine HAVE_FLTK_FULLSCREEN
 #cmakedefine HAVE_FLTK_CURSOR
 #cmakedefine ENABLE_NLS 1
+#cmakedefine HAVE_PAM
 
 /* MS Visual Studio 2008 and newer doesn't know ssize_t */
 #if defined(HAVE_GNUTLS) && defined(WIN32) && !defined(__MINGW32__)