diff -up chemtool-1.6.12/configure.ac.ld chemtool-1.6.12/configure.ac
--- chemtool-1.6.12/configure.ac.ld 2008-03-24 15:39:34.000000000 +0100
+++ chemtool-1.6.12/configure.ac 2010-02-14 21:44:08.000000000 +0100
@@ -56,6 +56,7 @@ dnl AC_MSG_RESULT using GTK2 : $use_gtk2
dnl Checks for header files.
AC_PATH_X
+AC_CHECK_LIB(X11, XCreatePixmap)
AC_HEADER_DIRENT
AC_HEADER_STDC