Sync from cvs.

[gnulib.git] / m4 / bison.m4

diff --git a/m4/bison.m4 b/m4/bison.m4
index 273b641..892293a 100644 (file)
--- a/m4/bison.m4
+++ b/m4/bison.m4
@@ -7,7 +7,17 @@
 
 AC_DEFUN([gl_BISON],
 [
+dnl All this cruft, which tries to fail harmlessly when bison is not present,
+dnl will no longer be necessary after we require an Automake release 1.10 or
+dnl later, as those avoid generating .c files from .y when not in maintainer
+dnl mode.  This is currently a fork from the GNULIB version of this file.
   # getdate.y works with bison only.
-  : ${YACC='bison -y'}
-  AC_SUBST(YACC)
+  AM_MISSING_PROG(YACC, bison -y)
+  AC_ARG_VAR(YACC,
+[The `Yet Another C Compiler' implementation to use.  Defaults to `bison -y'.
+Values other than `bison -y' will most likely break on most systems.])
+  AC_ARG_VAR(YFLAGS,
+[YFLAGS contains the list arguments that will be passed by default to Bison.
+This script will default YFLAGS to the empty string to avoid a default value of
+`-d' given by some make applications.])
 ])