背景
编译bison出错
configure.ac:233: error: possibly undefined macro: AC_PROG_GNU_M4
If this token and others are legitimate, please use m4_pattern_allow.
See the Autoconf documentation.
autoreconf: /usr/local/bin/autoconf failed with exit status: 1
./bootstrap: autoreconf failed
bison-3.4/m4/m4.m4定义了 AC_PROG_GNU_M4宏定义
# AC_PROG_GNU_M4
# --------------
# Check for GNU M4, at least 1.4.6 (all earlier versions had bugs in
# trace support and regexp support):
# https://lists.gnu.org/archive/html/bug-gnu-utils/2006-11/msg00096.html
# https://lists.gnu.org/archive/html/bug-autoconf/2009-07/msg00023.html
# Also, check whether --error-output (through 1.4.x) or --debugfile (2.0)
# is supported, and AC_SUBST M4_DEBUGFILE accordingly.
# Also avoid versions of m4 that trigger strstr bugs.
AC_DEFUN([AC_PROG_GNU_M4],
[AC_ARG_VAR([M4], [Location of GNU M4 1.4.6 or later. Defaults to the first
program of 'm4', 'gm4', or 'gnum4' on PATH that meets Autoconf needs.])
AC_CACHE_CHECK([for GNU M4 that supports accurate traces], [ac_cv_path_M4],
[rm -f conftest.m4f
ac_had_posixly_correct=${POSIXLY_CORRECT:+yes}
AS_UNSET([POSIXLY_CORRECT])
AC_PATH_PROGS_FEATURE_CHECK([M4], [m4 gm4 gnum4],