* data/glr.cc, data/lalr1.cc: Using %defines is mandatory.

[bison.git] / data / lalr1.cc

diff --git a/data/lalr1.cc b/data/lalr1.cc
index abf459f4404fc1d67656baa165d3d56947004ba0..527a8de796b146e9d9adf8fa50307fefc0f8a386 100644 (file)
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -20,6 +20,11 @@ m4_divert(-1)
 # 02110-1301  USA
 
 m4_include(b4_pkgdatadir/[c++.m4])
+
+# The header is mandatory.
+b4_defines_if([],
+              [m4_fatal(b4_skeleton[: using %defines is mandatory])])
+
 # Backward compatibility.
 m4_define([b4_location_constructors])
 m4_include(b4_pkgdatadir/[location.cc])