[PATCH] AC_INIT: add --runstatedir option to configure

[Eric Blake]

http://lwn.net/Articles/436012/ documents that many distros
are now preferring to use /run rather than /var/run for
storage of pid files and other per-process temporary files
that must not be cleaned out during arbitrary TMPDIR sweeps.
As such, the GNU Coding Standards were recently changed to
recommend a new configure option to make it easy to choose
this directory at configure time.  This patch adds support
for the option to all configure scripts built by autoconf.

* general.m4 (_AC_INIT_PARSE_ARGS): Add new directory option.
(_AC_INIT_HELP): Document it.
* doc/autoconf.texi (Installation Directory Variables): Document
new option.
(Site Defaults): Mention typical use within a distro.
* NEWS: Mention the addition.

Signed-off-by: Eric Blake <address@hidden>
---

I don't plan to push this until the make-stds.texi changes actually
go live (particarly in case we change our minds on what to name it,
but also to give a chance for anyone to review the wording used in
my documentation below).  But this is all the more autoconf has to
do in order to support the new option.

 NEWS                    |  5 +++++
 doc/autoconf.texi       | 14 +++++++++++++-
 lib/autoconf/general.m4 | 13 ++++++++++++-
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index de9d915..130cf3b 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,11 @@ GNU Autoconf NEWS - User visible changes.

 * Noteworthy changes in release ?.? (????-??-??) [?]

+** Configure scripts now supports a '--runstatedir' option, which
+   defaults to '${localstatedir}/run', but can be used to place
+   per-process temporary runtime files (such as pid files) into '/run'
+   instead of '/var/run'.
+
 ** The use of the long-deprecated name 'configure.in' for the autoconf
    input file now elicits a warning in the 'obsolete' category.

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 26e7b17..4932067 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -2826,7 +2826,18 @@ Installation Directory Variables

 @defvar localstatedir
 @ovindex localstatedir
-The directory for installing modifiable single-machine data.
+The directory for installing modifiable single-machine data.  Content in
+this directory typically survives a reboot.
address@hidden defvar
+
address@hidden runstatedir
address@hidden runstatedir
+The directory for installing temporary modifiable single-machine data.
+Content in this directory survives as long as the process is running
+(such as pid files), as contrasted with @file{/tmp} that may be
+periodically cleaned.  Conversely, this directory is typically cleaned
+on a reboot.  By default, this is a subdirectory of
address@hidden
 @end defvar

 @defvar mandir
@@ -22606,6 +22617,7 @@ Site Defaults
 test "$exec_prefix" = NONE && exec_prefix=/usr/local/gnu
 test "$sharedstatedir" = 'address@hidden@}/com' && sharedstatedir=/var
 test "$localstatedir" = 'address@hidden@}/var' && localstatedir=/var
+test "$runstatedir" = 'address@hidden@}/run' && runstatedir=/run

 # Give Autoconf 2.x generated configure scripts a shared default
 # cache file for feature test results, architecture-specific.
diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index 70b0168..1ce9922 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -586,6 +586,7 @@ AC_SUBST([datadir],        ['${datarootdir}'])dnl
 AC_SUBST([sysconfdir],     ['${prefix}/etc'])dnl
 AC_SUBST([sharedstatedir], ['${prefix}/com'])dnl
 AC_SUBST([localstatedir],  ['${prefix}/var'])dnl
+AC_SUBST([runstatedir],    ['${localstatedir}/run'])dnl
 AC_SUBST([includedir],     ['${prefix}/include'])dnl
 AC_SUBST([oldincludedir],  ['/usr/include'])dnl
 AC_SUBST([docdir],         [m4_ifset([AC_PACKAGE_TARNAME],
@@ -812,6 +813,15 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;

+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -921,7 +931,7 @@ fi
 for ac_var in  exec_prefix prefix bindir sbindir libexecdir datarootdir \
                datadir sysconfdir sharedstatedir localstatedir includedir \
                oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-               libdir localedir mandir
+               libdir localedir mandir runstatedir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1058,6 +1068,7 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
-- 
1.8.3.1