--- ical-2.3.3/Makefile.in.no-locincpth	2004-03-11 12:26:55.000000000 +0100
+++ ical-2.3.3/Makefile.in	2010-02-18 11:08:36.000000000 +0100
@@ -64,7 +64,7 @@
    CXXFLAGS = $(OPTF)
     CXXINCS = -I. -I$(srcdir) -I$(srcdir)/calendar \
               -I$(srcdir)/types -I$(srcdir)/time \
-              $(X_CFLAGS) -I@TCL_INCDIR@ -I@TK_INCDIR@
+              $(X_CFLAGS) @TCLTK_CPPFLAGS@
 
      CFLAGS = $(OPTF) -I. -I$(srcdir) $(X_CFLAGS)
 
--- ical-2.3.3/configure.in.no-locincpth	2007-09-19 13:43:24.000000000 +0200
+++ ical-2.3.3/configure.in	2010-02-18 11:08:36.000000000 +0100
@@ -233,8 +233,11 @@
 AC_MSG_RESULT($is_good_tk_version)
 if test "$is_good_tk_version" = "no"; then exit 1; fi
 
-TCL_INCDIR="$tclhdir"
-TK_INCDIR="$tkhdir"
+for dir in $tclhdir $tkhdir; do
+  if [[ "x$dir" != "x/usr/include" -a "x$dir" != "x$dir/usr/local/include" ]]; then
+    TCLTK_CPPFLAGS="$TCLTK_CPPFLAGS -I$dir"
+  fi
+done
 
 #### Export variables discovered during Tcl/Tk configuration
 
@@ -247,8 +250,7 @@
 AC_SUBST(TK_PREFIX)
 AC_SUBST(TK_EXEC_PREFIX)
 AC_SUBST(TK_XINCLUDES)
-AC_SUBST(TCL_INCDIR)
-AC_SUBST(TK_INCDIR)
+AC_SUBST(TCLTK_CPPFLAGS)
 
 #### Find names of script files for use in stand-alone installation
 TCL_SCRIPT_DIR="$TCL_PREFIX/lib/tcl$TCL_VERSION"