config: use existing variables KEYSYMDEF_H and XF86KEYSYM_H

These automake variables are not currently used.
The variable KS_HEADERS is not required anymore.

Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
Signed-off-by: Gaetan Nadon <memsize@videotron.ca>
diff --git a/configure.ac b/configure.ac
index b982839..7f8f9fa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -87,9 +87,6 @@
 AC_MSG_RESULT([$XF86KEYSYM_H])
 AC_SUBST([XF86KEYSYM_H])
 
-# Aggregate the headers full paths for makekeys
-AC_SUBST([KS_HEADERS], ['$(KEYSYMDEF_H) $(XF86KEYSYM_H)'])
-
 # Define a configuration option for the XKB config root
 AC_ARG_WITH([xkb_config_root],
     [AS_HELP_STRING([--with-xkb-config-root=<paths>],
diff --git a/src/makekeys/Makefile.am b/src/makekeys/Makefile.am
index 44d5081..1847034 100644
--- a/src/makekeys/Makefile.am
+++ b/src/makekeys/Makefile.am
@@ -10,4 +10,4 @@
 
 ks_tables.h: makekeys$(EXEEXT)
 	@rm -f $@
-	cat $(KS_HEADERS) | $(builddir)/makekeys$(EXEEXT) > $@
+	cat $(KEYSYMDEF_H) $(XF86KEYSYM_H) | $(builddir)/makekeys$(EXEEXT) > $@