#include "symtab.h"
#include "tables.h"
+# define ARRAY_CARDINALITY(Array) (sizeof (Array) / sizeof *(Array))
static struct obstack format_obstack;
{
FILE *in;
int filter_fd[2];
- char const *argv[9];
+ char const *argv[10];
pid_t pid;
/* Compute the names of the package data dir and skeleton files. */
{
int i = 0;
argv[i++] = m4;
+
+ /* When POSIXLY_CORRECT is set, GNU M4 1.6 and later disable GNU
+ extensions, which Bison's skeletons depend on. With older M4,
+ it has no effect. M4 1.4.12 added a -g/--gnu command-line
+ option to make it explicit that a program wants GNU M4
+ extensions even when POSIXLY_CORRECT is set.
+
+ See the thread starting at
+ <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
+ for details. */
+ if (*M4_GNU_OPTION)
+ argv[i++] = M4_GNU_OPTION;
+
argv[i++] = "-I";
argv[i++] = pkgdatadir;
if (trace_flag & trace_m4)
argv[i++] = full_m4bison;
argv[i++] = full_skeleton;
argv[i++] = NULL;
+ aver (i <= ARRAY_CARDINALITY (argv));
}
- /* When POSIXLY_CORRECT is set, some future versions of GNU M4 (most likely
- 2.0) may drop some of the GNU extensions that Bison's skeletons depend
- upon. So that the next release of Bison is forward compatible with those
- future versions of GNU M4, we unset POSIXLY_CORRECT here.
-
- FIXME: A user might set POSIXLY_CORRECT to affect processes run from
- macros like m4_syscmd in a custom skeleton. For now, Bison makes no
- promises about the behavior of custom skeletons, so this scenario is not a
- concern. However, we eventually want to eliminate this shortcoming. The
- next release of GNU M4 (1.4.12 or 1.6) will accept the -g command-line
- option as a no-op, and later releases will accept it to indicate that
- POSIXLY_CORRECT should be ignored. Once the GNU M4 versions that accept
- -g are pervasive, Bison should use -g instead of unsetting
- POSIXLY_CORRECT.
- See the thread starting at
- <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
- for details. */
- unsetenv ("POSIXLY_CORRECT");
init_subpipe ();
pid = create_subpipe (argv, filter_fd);
free (full_m4sugar);