configure.ac: check for bison

configure.ac

@@ -1122,10 +1122,13 @@ fi
 # Bison is used to generate the C expression parser.  The generated
 # parser is part of the distribution, though.
 AC_PATH_PROG([YACC], [yacc])
-AC_MSG_CHECKING(yacc $YACC)
 if test "x$YACC" = "x"; then
     AC_MSG_ERROR([Compiler yacc not available])
 fi
+AC_PATH_PROG([BISON], [bison])
+if test "x$BISON" = "x"; then
+    AC_MSG_ERROR([Compiler bison not available])
+fi
 
 AM_CONDITIONAL([BUILD_GCC_PLUGIN], [test "x$build_gcc_plugin" = "xyes"])
 AM_CONDITIONAL([HAVE_GUILE], [test "x$GUILE" != "x"])