1# parse-datetime.m4 serial 25
2dnl Copyright (C) 2002-2006, 2008-2020 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl Define HAVE_COMPOUND_LITERALS if the C compiler supports compound literals
8dnl as in ISO C99.
9dnl Note that compound literals such as (struct s) { 3, 4 } can be used for
10dnl initialization of stack-allocated variables, but are not constant
11dnl expressions and therefore cannot be used as initializer for global or
12dnl static variables (even though gcc supports this in pre-C99 mode).
13AC_DEFUN([gl_C_COMPOUND_LITERALS],
14[
15  AC_CACHE_CHECK([for compound literals], [gl_cv_compound_literals],
16  [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[struct s { int i, j; };]],
17      [[struct s t = (struct s) { 3, 4 };
18        if (t.i != 0) return 0;]])],
19    gl_cv_compound_literals=yes,
20    gl_cv_compound_literals=no)])
21  if test $gl_cv_compound_literals = yes; then
22    AC_DEFINE([HAVE_COMPOUND_LITERALS], [1],
23      [Define if you have compound literals.])
24  fi
25])
26
27AC_DEFUN([gl_PARSE_DATETIME],
28[
29  dnl parse-datetime.c is generated from parse-datetime.y. It requires bison,
30  dnl because parse-datetime.y uses bison specific features. It requires at
31  dnl least bison-2.4 for %define api.pure.
32  dnl bison is only needed for the maintainer (who touches parse-datetime.y).
33  dnl But in order to avoid separate Makefiles or --enable-maintainer-mode,
34  dnl we put the rule in general Makefile. Now, some people carelessly touch
35  dnl the files or have a broken "make" program, hence the parse-datetime.c
36  dnl rule will sometimes fire. To avoid an error, defines PARSE_DATETIME_BISON
37  dnl to ":" if it is not present or too old.
38  gl_PROG_BISON([PARSE_DATETIME_BISON], [2.4])
39
40  dnl Prerequisites of lib/parse-datetime.h.
41  AC_REQUIRE([AM_STDBOOL_H])
42  AC_REQUIRE([gl_TIMESPEC])
43  AC_REQUIRE([AC_C_RESTRICT])
44
45  dnl Prerequisites of lib/parse-datetime.y.
46  AC_REQUIRE([gl_BISON])
47  AC_REQUIRE([gl_C_COMPOUND_LITERALS])
48  AC_STRUCT_TIMEZONE
49  AC_REQUIRE([gl_CLOCK_TIME])
50  AC_REQUIRE([gl_TM_GMTOFF])
51])
52