Simplify GNULIB_* variable initializations.

* modules/gnulib-common.m4 (gl_MODULE_INDICATOR_INIT_VARIABLE): New
macro.
* m4/arpa_inet_h.m4 (gl_ARPA_INET_H_DEFAULTS): Use it.
* m4/ctype.m4 (gl_CTYPE_H_DEFAULTS): Likewise.
* m4/dirent_h.m4 (gl_DIRENT_H_DEFAULTS): Likewise.
* m4/fcntl_h.m4 (gl_FCNTL_H_DEFAULTS): Likewise.
* m4/fnmatch_h.m4 (gl_FNMATCH_H_DEFAULTS): Likewise.
* m4/glob_h.m4 (gl_GLOB_H_DEFAULTS): Likewise.
* m4/iconv_h.m4 (gl_ICONV_H_DEFAULTS): Likewise.
* m4/inttypes.m4 (gl_INTTYPES_H_DEFAULTS): Likewise.
* m4/langinfo_h.m4 (gl_LANGINFO_H_DEFAULTS): Likewise.
* m4/locale_h.m4 (gl_LOCALE_H_DEFAULTS): Likewise.
* m4/malloc_h.m4 (gl_MALLOC_H_DEFAULTS): Likewise.
* m4/math_h.m4 (gl_MATH_H_DEFAULTS): Likewise.
* m4/monetary_h.m4 (gl_MONETARY_H_DEFAULTS): Likewise.
* m4/netdb_h.m4 (gl_NETDB_H_DEFAULTS): Likewise.
* m4/poll_h.m4 (gl_POLL_H_DEFAULTS): Likewise.
* m4/pthread_h.m4 (gl_PTHREAD_H_DEFAULTS): Likewise.
* m4/pty_h.m4 (gl_PTY_H_DEFAULTS): Likewise.
* m4/sched_h.m4 (gl_SCHED_H_DEFAULTS): Likewise.
* m4/search_h.m4 (gl_SEARCH_H_DEFAULTS): Likewise.
* m4/signal_h.m4 (gl_SIGNAL_H_DEFAULTS): Likewise.
* m4/spawn_h.m4 (gl_SPAWN_H_DEFAULTS): Likewise.
* m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Likewise.
* m4/stdlib_h.m4 (gl_STDLIB_H_DEFAULTS): Likewise.
* m4/string_h.m4 (gl_HEADER_STRING_H_DEFAULTS): Likewise.
* m4/strings_h.m4 (gl_HEADER_STRINGS_H_DEFAULTS): Likewise.
* m4/sys_file_h.m4 (gl_HEADER_SYS_FILE_H_DEFAULTS): Likewise.
* m4/sys_ioctl_h.m4 (gl_SYS_IOCTL_H_DEFAULTS): Likewise.
* m4/sys_random_h.m4 (gl_SYS_RANDOM_H_DEFAULTS): Likewise.
* m4/sys_resource_h.m4 (gl_SYS_RESOURCE_H_DEFAULTS): Likewise.
* m4/sys_select_h.m4 (gl_SYS_SELECT_H_DEFAULTS): Likewise.
* m4/sys_socket_h.m4 (gl_SYS_SOCKET_H_DEFAULTS): Likewise.
* m4/sys_stat_h.m4 (gl_SYS_STAT_H_DEFAULTS): Likewise.
* m4/sys_time_h.m4 (gl_HEADER_SYS_TIME_H_DEFAULTS): Likewise.
* m4/sys_times_h.m4 (gl_SYS_TIMES_H_DEFAULTS): Likewise.
* m4/sys_utsname_h.m4 (gl_SYS_UTSNAME_H_DEFAULTS): Likewise.
* m4/sys_wait_h.m4 (gl_SYS_WAIT_H_DEFAULTS): Likewise.
* m4/termios_h.m4 (gl_TERMIOS_H_DEFAULTS): Likewise.
* m4/threads.m4 (gl_THREADS_H_DEFAULTS): Likewise.
* m4/time_h.m4 (gl_HEADER_TIME_H_DEFAULTS): Likewise.
* m4/uchar.m4 (gl_UCHAR_H_DEFAULTS): Likewise.
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Likewise.
* m4/utime_h.m4 (gl_UTIME_H_DEFAULTS): Likewise.
* m4/wchar_h.m4 (gl_WCHAR_H_DEFAULTS): Likewise.
* m4/wctype_h.m4 (gl_WCTYPE_H_DEFAULTS): Likewise.

1 files changed, 11 insertions, 1 deletions

diff --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4
index f2eff10de6..8faec20f0d 100644
--- a/m4/gnulib-common.m4
+++ b/m4/gnulib-common.m4
@@ -1,4 +1,4 @@
-# gnulib-common.m4 serial 63
+# gnulib-common.m4 serial 64
 dnl Copyright (C) 2007-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -357,6 +357,16 @@ AC_DEFUN([gl_COMMON_BODY], [
   export LIBC_FATAL_STDERR_
 ])
 
+# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename])
+# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename], [initialvalue])
+# initializes the shell variable that indicates the presence of the given module
+# as a C preprocessor expression.
+AC_DEFUN([gl_MODULE_INDICATOR_INIT_VARIABLE],
+[
+  [$1]=m4_if([$2], , [0], [$2])
+  AC_SUBST([$1])
+])
+
 # gl_MODULE_INDICATOR_CONDITION
 # expands to a C preprocessor expression that evaluates to 1 or 0, depending
 # whether a gnulib module that has been requested shall be considered present