This patch makes configure not ignore user-set CFLAGS.
--- gltron-0.70final.orig/configure.in
+++ gltron-0.70final/configure.in
@@ -17,7 +17,7 @@
AC_PROG_RANLIB
dnl CFLAGS set-up
-CFLAGS="-DSEPARATOR=\"'/'\""
+CFLAGS="$CFLAGS -DSEPARATOR=\"'/'\""
dnl CFLAGS="-ansi -pedantic"
dnl CXXFLAGS=""
dnl CPPFLAGS=""