Provide glthread/lock.h implementation in terms of Guile threads.

Fixes <http://bugs.gnu.org/14404>.
Thanks to Paul Eggert <eggert@cs.ucla.edu> for the suggestion.

* m4/gnulib-cache.m4: Avoid 'lock' module.
* m4/lock.m4, m4/threadlib.m4, lib/glthread/threadlib.c,
  lib/glthread/lock.c: Remove.
* lib/glthread/lock.h: Rewrite in terms of libguile/threads.h.
* m4/gnulib-common.m4, m4/gnulib-comp.m4, lib/Makefile.am,
  lib/unistd.in.h, maint.mk : Update, from Gnulib v0.1-92-g546ff82.

* configure.ac (GNULIB_LOCK): Define 'GNULIB_LOCK'.  Define
  'USE_POSIX_THREADS' when building with pthread support.
* Makefile.am (noinst_HEADERS): New variable.
  (BUILT_SOURCES): Add libguile/scmconfig.h.
  (libguile/scmconfig.h): New target.

5 files changed, 59 insertions, 426 deletions

diff --git a/m4/gnulib-cache.m4 b/m4/gnulib-cache.m4
index fc7391cda..9e095da7c 100644
--- a/m4/gnulib-cache.m4
+++ b/m4/gnulib-cache.m4
@@ -27,7 +27,7 @@
 
 
 # Specification in the form of a command-line invocation:
-#   gnulib-tool --import --dir=. --local-dir=gnulib-local --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --lgpl=3 --no-conditional-dependencies --libtool --macro-prefix=gl --no-vc-files accept alignof alloca-opt announce-gen autobuild bind byteswap c-strcase canonicalize-lgpl ceil clock-time close connect copysign dirfd duplocale environ extensions flock floor fpieee frexp fstat fsync full-read full-write func gendocs getaddrinfo getlogin getpeername getsockname getsockopt git-version-gen gitlog-to-changelog gnu-web-doc-update gnupload havelib iconv_open-utf inet_ntop inet_pton isfinite isinf isnan ldexp lib-symbol-versions lib-symbol-visibility libunistring link listen localcharset locale log1p lstat maintainer-makefile malloc-gnu malloca mkdir mkstemp nl_langinfo nproc open pipe-posix pipe2 poll putenv readlink recv recvfrom regex rename rmdir select send sendto setenv setsockopt shutdown socket stat-time stdlib strftime striconveh string sys_stat time times trunc unistd verify vsnprintf warnings wchar
+#   gnulib-tool --import --dir=. --local-dir=gnulib-local --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=lock --lgpl=3 --no-conditional-dependencies --libtool --macro-prefix=gl --no-vc-files accept alignof alloca-opt announce-gen autobuild bind byteswap c-strcase canonicalize-lgpl ceil clock-time close connect copysign dirfd duplocale environ extensions flock floor fpieee frexp fstat fsync full-read full-write func gendocs getaddrinfo getlogin getpeername getsockname getsockopt git-version-gen gitlog-to-changelog gnu-web-doc-update gnupload havelib iconv_open-utf inet_ntop inet_pton isfinite isinf isnan ldexp lib-symbol-versions lib-symbol-visibility libunistring link listen localcharset locale log1p lstat maintainer-makefile malloc-gnu malloca mkdir mkstemp nl_langinfo nproc open pipe-posix pipe2 poll putenv readlink recv recvfrom regex rename rmdir select send sendto setenv setsockopt shutdown socket stat-time stdlib strftime striconveh string sys_stat time times trunc unistd verify vsnprintf warnings wchar
 
 # Specification in the form of a few gnulib-tool.m4 macro invocations:
 gl_LOCAL_DIR([gnulib-local])
@@ -126,7 +126,7 @@ gl_MODULES([
   warnings
   wchar
 ])
-gl_AVOID([])
+gl_AVOID([lock])
 gl_SOURCE_BASE([lib])
 gl_M4_BASE([m4])
 gl_PO_BASE([])
diff --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4
index 3b61b239b..20ce40e74 100644
--- a/m4/gnulib-common.m4
+++ b/m4/gnulib-common.m4
@@ -379,3 +379,59 @@ AC_DEFUN([gl_CACHE_VAL_SILENT],
 # AS_VAR_COPY was added in autoconf 2.63b
 m4_define_default([AS_VAR_COPY],
 [AS_LITERAL_IF([$1[]$2], [$1=$$2], [eval $1=\$$2])])
+
+# AC_PROG_SED was added in autoconf 2.59b
+m4_ifndef([AC_PROG_SED],
+[AC_DEFUN([AC_PROG_SED],
+[AC_CACHE_CHECK([for a sed that does not truncate output], ac_cv_path_SED,
+    [dnl ac_script should not contain more than 99 commands (for HP-UX sed),
+     dnl but more than about 7000 bytes, to catch a limit in Solaris 8 /usr/ucb/sed.
+     ac_script=s/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb/
+     for ac_i in 1 2 3 4 5 6 7; do
+       ac_script="$ac_script$as_nl$ac_script"
+     done
+     echo "$ac_script" 2>/dev/null | sed 99q >conftest.sed
+     AS_UNSET([ac_script])
+     if test -z "$SED"; then
+       ac_path_SED_found=false
+       _AS_PATH_WALK([], [
+         for ac_prog in sed gsed; do
+           for ac_exec_ext in '' $ac_executable_extensions; do
+             ac_path_SED="$as_dir/$ac_prog$ac_exec_ext"
+             AS_EXECUTABLE_P(["$ac_path_SED"]) || continue
+             case `"$ac_path_SED" --version 2>&1` in
+               *GNU*) ac_cv_path_SED=$ac_path_SED ac_path_SED_found=:;;
+               *)
+                 ac_count=0
+                 _AS_ECHO_N([0123456789]) >conftest.in
+                 while :
+                 do
+                   cat conftest.in conftest.in >conftest.tmp
+                   mv conftest.tmp conftest.in
+                   cp conftest.in conftest.nl
+                   echo >> conftest.nl
+                   "$ac_path_SED" -f conftest.sed <conftest.nl >conftest.out 2>/dev/null || break
+                   diff conftest.out conftest.nl >/dev/null 2>&1 || break
+                   ac_count=`expr $ac_count + 1`
+                   if test $ac_count -gt ${ac_path_SED_max-0}; then
+                     # Best so far, but keep looking for better
+                     ac_cv_path_SED=$ac_path_SED
+                     ac_path_SED_max=$ac_count
+                   fi
+                   test $ac_count -gt 10 && break
+                 done
+                 rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+             esac
+             $ac_path_SED_found && break 3
+           done
+         done])
+       if test -z "$ac_cv_path_SED"; then
+         AC_ERROR([no acceptable sed could be found in \$PATH])
+       fi
+     else
+       ac_cv_path_SED=$SED
+     fi
+ SED="$ac_cv_path_SED"
+ AC_SUBST([SED])dnl
+ rm -f conftest.sed
+])])])
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index b333d6aed..429fee422 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -133,7 +133,6 @@ AC_DEFUN([gl_EARLY],
   # Code from module localcharset:
   # Code from module locale:
   # Code from module localeconv:
-  # Code from module lock:
   # Code from module log:
   # Code from module log1p:
   # Code from module lstat:
@@ -219,8 +218,6 @@ AC_DEFUN([gl_EARLY],
   # Code from module sys_types:
   # Code from module sys_uio:
   # Code from module tempname:
-  # Code from module threadlib:
-  gl_THREADLIB_EARLY
   # Code from module time:
   # Code from module time_r:
   # Code from module times:
@@ -529,8 +526,6 @@ AC_SUBST([LTALLOCA])
     gl_PREREQ_LOCALECONV
   fi
   gl_LOCALE_MODULE_INDICATOR([localeconv])
-  gl_LOCK
-  gl_MODULE_INDICATOR([lock])
   AC_REQUIRE([gl_FUNC_LOG])
   if test $REPLACE_LOG = 1; then
     AC_LIBOBJ([log])
@@ -549,6 +544,7 @@ AC_SUBST([LTALLOCA])
   gl_SYS_STAT_MODULE_INDICATOR([lstat])
   AC_CONFIG_COMMANDS_PRE([m4_ifdef([AH_HEADER],
     [AC_SUBST([CONFIG_INCLUDE], m4_defn([AH_HEADER]))])])
+  AC_REQUIRE([AC_PROG_SED])
   gl_FUNC_MALLOC_GNU
   if test $REPLACE_MALLOC = 1; then
     AC_LIBOBJ([malloc])
@@ -800,7 +796,6 @@ AC_SUBST([LTALLOCA])
   gl_HEADER_SYS_UIO
   AC_PROG_MKDIR_P
   gl_FUNC_GEN_TEMPNAME
-  gl_THREADLIB
   gl_HEADER_TIME_H
   gl_TIME_R
   if test $HAVE_LOCALTIME_R = 0 || test $REPLACE_LOCALTIME_R = 1; then
@@ -1054,9 +1049,6 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/getsockopt.c
   lib/gettext.h
   lib/gettimeofday.c
-  lib/glthread/lock.c
-  lib/glthread/lock.h
-  lib/glthread/threadlib.c
   lib/iconv.c
   lib/iconv.in.h
   lib/iconv_close.c
@@ -1294,7 +1286,6 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/locale-zh.m4
   m4/locale_h.m4
   m4/localeconv.m4
-  m4/lock.m4
   m4/log.m4
   m4/log1p.m4
   m4/longlong.m4
@@ -1372,7 +1363,6 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/sys_types_h.m4
   m4/sys_uio_h.m4
   m4/tempname.m4
-  m4/threadlib.m4
   m4/time_h.m4
   m4/time_r.m4
   m4/times.m4
diff --git a/m4/lock.m4 b/m4/lock.m4
deleted file mode 100644
index 73a3c54ce..000000000
--- a/m4/lock.m4
+++ /dev/null
@@ -1,42 +0,0 @@
-# lock.m4 serial 13 (gettext-0.18.2)
-dnl Copyright (C) 2005-2014 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Bruno Haible.
-
-AC_DEFUN([gl_LOCK],
-[
-  AC_REQUIRE([gl_THREADLIB])
-  if test "$gl_threads_api" = posix; then
-    # OSF/1 4.0 and Mac OS X 10.1 lack the pthread_rwlock_t type and the
-    # pthread_rwlock_* functions.
-    AC_CHECK_TYPE([pthread_rwlock_t],
-      [AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],
-         [Define if the POSIX multithreading library has read/write locks.])],
-      [],
-      [#include <pthread.h>])
-    # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
-    AC_COMPILE_IFELSE([
-      AC_LANG_PROGRAM(
-        [[#include <pthread.h>]],
-        [[
-#if __FreeBSD__ == 4
-error "No, in FreeBSD 4.0 recursive mutexes actually don't work."
-#elif (defined __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ \
-       && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 1070)
-error "No, in Mac OS X < 10.7 recursive mutexes actually don't work."
-#else
-int x = (int)PTHREAD_MUTEX_RECURSIVE;
-return !x;
-#endif
-        ]])],
-      [AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], [1],
-         [Define if the <pthread.h> defines PTHREAD_MUTEX_RECURSIVE.])])
-  fi
-  gl_PREREQ_LOCK
-])
-
-# Prerequisites of lib/glthread/lock.c.
-AC_DEFUN([gl_PREREQ_LOCK], [:])
diff --git a/m4/threadlib.m4 b/m4/threadlib.m4
deleted file mode 100644
index a88170261..000000000
--- a/m4/threadlib.m4
+++ /dev/null
@@ -1,371 +0,0 @@
-# threadlib.m4 serial 10 (gettext-0.18.2)
-dnl Copyright (C) 2005-2014 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Bruno Haible.
-
-dnl gl_THREADLIB
-dnl ------------
-dnl Tests for a multithreading library to be used.
-dnl If the configure.ac contains a definition of the gl_THREADLIB_DEFAULT_NO
-dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the
-dnl default is 'no', otherwise it is system dependent. In both cases, the user
-dnl can change the choice through the options --enable-threads=choice or
-dnl --disable-threads.
-dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
-dnl USE_PTH_THREADS, USE_WINDOWS_THREADS
-dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
-dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
-dnl libtool).
-dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
-dnl programs that really need multithread functionality. The difference
-dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
-dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
-dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
-dnl multithread-safe programs.
-
-AC_DEFUN([gl_THREADLIB_EARLY],
-[
-  AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
-])
-
-dnl The guts of gl_THREADLIB_EARLY. Needs to be expanded only once.
-
-AC_DEFUN([gl_THREADLIB_EARLY_BODY],
-[
-  dnl Ordering constraints: This macro modifies CPPFLAGS in a way that
-  dnl influences the result of the autoconf tests that test for *_unlocked
-  dnl declarations, on AIX 5 at least. Therefore it must come early.
-  AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl
-  AC_BEFORE([$0], [gl_ARGP])dnl
-
-  AC_REQUIRE([AC_CANONICAL_HOST])
-  dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
-  dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
-  dnl AC_GNU_SOURCE.
-  m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
-    [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
-    [AC_REQUIRE([AC_GNU_SOURCE])])
-  dnl Check for multithreading.
-  m4_ifdef([gl_THREADLIB_DEFAULT_NO],
-    [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
-    [m4_divert_text([DEFAULTS], [gl_use_threads_default=])])
-  AC_ARG_ENABLE([threads],
-AC_HELP_STRING([--enable-threads={posix|solaris|pth|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
-AC_HELP_STRING([--disable-threads], [build without multithread safety])]),
-    [gl_use_threads=$enableval],
-    [if test -n "$gl_use_threads_default"; then
-       gl_use_threads="$gl_use_threads_default"
-     else
-changequote(,)dnl
-       case "$host_os" in
-         dnl Disable multithreading by default on OSF/1, because it interferes
-         dnl with fork()/exec(): When msgexec is linked with -lpthread, its
-         dnl child process gets an endless segmentation fault inside execvp().
-         dnl Disable multithreading by default on Cygwin 1.5.x, because it has
-         dnl bugs that lead to endless loops or crashes. See
-         dnl <http://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
-         osf*) gl_use_threads=no ;;
-         cygwin*)
-               case `uname -r` in
-                 1.[0-5].*) gl_use_threads=no ;;
-                 *)         gl_use_threads=yes ;;
-               esac
-               ;;
-         *)    gl_use_threads=yes ;;
-       esac
-changequote([,])dnl
-     fi
-    ])
-  if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
-    # For using <pthread.h>:
-    case "$host_os" in
-      osf*)
-        # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
-        # groks <pthread.h>. cc also understands the flag -pthread, but
-        # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
-        # 2. putting a flag into CPPFLAGS that has an effect on the linker
-        # causes the AC_LINK_IFELSE test below to succeed unexpectedly,
-        # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
-        CPPFLAGS="$CPPFLAGS -D_REENTRANT"
-        ;;
-    esac
-    # Some systems optimize for single-threaded programs by default, and
-    # need special flags to disable these optimizations. For example, the
-    # definition of 'errno' in <errno.h>.
-    case "$host_os" in
-      aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
-      solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
-    esac
-  fi
-])
-
-dnl The guts of gl_THREADLIB. Needs to be expanded only once.
-
-AC_DEFUN([gl_THREADLIB_BODY],
-[
-  AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
-  gl_threads_api=none
-  LIBTHREAD=
-  LTLIBTHREAD=
-  LIBMULTITHREAD=
-  LTLIBMULTITHREAD=
-  if test "$gl_use_threads" != no; then
-    dnl Check whether the compiler and linker support weak declarations.
-    AC_CACHE_CHECK([whether imported symbols can be declared weak],
-      [gl_cv_have_weak],
-      [gl_cv_have_weak=no
-       dnl First, test whether the compiler accepts it syntactically.
-       AC_LINK_IFELSE(
-         [AC_LANG_PROGRAM(
-            [[extern void xyzzy ();
-#pragma weak xyzzy]],
-            [[xyzzy();]])],
-         [gl_cv_have_weak=maybe])
-       if test $gl_cv_have_weak = maybe; then
-         dnl Second, test whether it actually works. On Cygwin 1.7.2, with
-         dnl gcc 4.3, symbols declared weak always evaluate to the address 0.
-         AC_RUN_IFELSE(
-           [AC_LANG_SOURCE([[
-#include <stdio.h>
-#pragma weak fputs
-int main ()
-{
-  return (fputs == NULL);
-}]])],
-           [gl_cv_have_weak=yes],
-           [gl_cv_have_weak=no],
-           [dnl When cross-compiling, assume that only ELF platforms support
-            dnl weak symbols.
-            AC_EGREP_CPP([Extensible Linking Format],
-              [#ifdef __ELF__
-               Extensible Linking Format
-               #endif
-              ],
-              [gl_cv_have_weak="guessing yes"],
-              [gl_cv_have_weak="guessing no"])
-           ])
-       fi
-      ])
-    if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
-      # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
-      # it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY.
-      AC_CHECK_HEADER([pthread.h],
-        [gl_have_pthread_h=yes], [gl_have_pthread_h=no])
-      if test "$gl_have_pthread_h" = yes; then
-        # Other possible tests:
-        #   -lpthreads (FSU threads, PCthreads)
-        #   -lgthreads
-        gl_have_pthread=
-        # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
-        # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
-        # the second one only in libpthread, and lock.c needs it.
-        AC_LINK_IFELSE(
-          [AC_LANG_PROGRAM(
-             [[#include <pthread.h>]],
-             [[pthread_mutex_lock((pthread_mutex_t*)0);
-               pthread_mutexattr_init((pthread_mutexattr_t*)0);]])],
-          [gl_have_pthread=yes])
-        # Test for libpthread by looking for pthread_kill. (Not pthread_self,
-        # since it is defined as a macro on OSF/1.)
-        if test -n "$gl_have_pthread"; then
-          # The program links fine without libpthread. But it may actually
-          # need to link with libpthread in order to create multiple threads.
-          AC_CHECK_LIB([pthread], [pthread_kill],
-            [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
-             # On Solaris and HP-UX, most pthread functions exist also in libc.
-             # Therefore pthread_in_use() needs to actually try to create a
-             # thread: pthread_create from libc will fail, whereas
-             # pthread_create will actually create a thread.
-             case "$host_os" in
-               solaris* | hpux*)
-                 AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
-                   [Define if the pthread_in_use() detection is hard.])
-             esac
-            ])
-        else
-          # Some library is needed. Try libpthread and libc_r.
-          AC_CHECK_LIB([pthread], [pthread_kill],
-            [gl_have_pthread=yes
-             LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
-             LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
-          if test -z "$gl_have_pthread"; then
-            # For FreeBSD 4.
-            AC_CHECK_LIB([c_r], [pthread_kill],
-              [gl_have_pthread=yes
-               LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
-               LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
-          fi
-        fi
-        if test -n "$gl_have_pthread"; then
-          gl_threads_api=posix
-          AC_DEFINE([USE_POSIX_THREADS], [1],
-            [Define if the POSIX multithreading library can be used.])
-          if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
-            if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
-              AC_DEFINE([USE_POSIX_THREADS_WEAK], [1],
-                [Define if references to the POSIX multithreading library should be made weak.])
-              LIBTHREAD=
-              LTLIBTHREAD=
-            fi
-          fi
-        fi
-      fi
-    fi
-    if test -z "$gl_have_pthread"; then
-      if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
-        gl_have_solaristhread=
-        gl_save_LIBS="$LIBS"
-        LIBS="$LIBS -lthread"
-        AC_LINK_IFELSE(
-          [AC_LANG_PROGRAM(
-             [[
-#include <thread.h>
-#include <synch.h>
-             ]],
-             [[thr_self();]])],
-          [gl_have_solaristhread=yes])
-        LIBS="$gl_save_LIBS"
-        if test -n "$gl_have_solaristhread"; then
-          gl_threads_api=solaris
-          LIBTHREAD=-lthread
-          LTLIBTHREAD=-lthread
-          LIBMULTITHREAD="$LIBTHREAD"
-          LTLIBMULTITHREAD="$LTLIBTHREAD"
-          AC_DEFINE([USE_SOLARIS_THREADS], [1],
-            [Define if the old Solaris multithreading library can be used.])
-          if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
-            AC_DEFINE([USE_SOLARIS_THREADS_WEAK], [1],
-              [Define if references to the old Solaris multithreading library should be made weak.])
-            LIBTHREAD=
-            LTLIBTHREAD=
-          fi
-        fi
-      fi
-    fi
-    if test "$gl_use_threads" = pth; then
-      gl_save_CPPFLAGS="$CPPFLAGS"
-      AC_LIB_LINKFLAGS([pth])
-      gl_have_pth=
-      gl_save_LIBS="$LIBS"
-      LIBS="$LIBS $LIBPTH"
-      AC_LINK_IFELSE(
-        [AC_LANG_PROGRAM([[#include <pth.h>]], [[pth_self();]])],
-        [gl_have_pth=yes])
-      LIBS="$gl_save_LIBS"
-      if test -n "$gl_have_pth"; then
-        gl_threads_api=pth
-        LIBTHREAD="$LIBPTH"
-        LTLIBTHREAD="$LTLIBPTH"
-        LIBMULTITHREAD="$LIBTHREAD"
-        LTLIBMULTITHREAD="$LTLIBTHREAD"
-        AC_DEFINE([USE_PTH_THREADS], [1],
-          [Define if the GNU Pth multithreading library can be used.])
-        if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
-          if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
-            AC_DEFINE([USE_PTH_THREADS_WEAK], [1],
-              [Define if references to the GNU Pth multithreading library should be made weak.])
-            LIBTHREAD=
-            LTLIBTHREAD=
-          fi
-        fi
-      else
-        CPPFLAGS="$gl_save_CPPFLAGS"
-      fi
-    fi
-    if test -z "$gl_have_pthread"; then
-      case "$gl_use_threads" in
-        yes | windows | win32) # The 'win32' is for backward compatibility.
-          if { case "$host_os" in
-                 mingw*) true;;
-                 *) false;;
-               esac
-             }; then
-            gl_threads_api=windows
-            AC_DEFINE([USE_WINDOWS_THREADS], [1],
-              [Define if the native Windows multithreading API can be used.])
-          fi
-          ;;
-      esac
-    fi
-  fi
-  AC_MSG_CHECKING([for multithread API to use])
-  AC_MSG_RESULT([$gl_threads_api])
-  AC_SUBST([LIBTHREAD])
-  AC_SUBST([LTLIBTHREAD])
-  AC_SUBST([LIBMULTITHREAD])
-  AC_SUBST([LTLIBMULTITHREAD])
-])
-
-AC_DEFUN([gl_THREADLIB],
-[
-  AC_REQUIRE([gl_THREADLIB_EARLY])
-  AC_REQUIRE([gl_THREADLIB_BODY])
-])
-
-
-dnl gl_DISABLE_THREADS
-dnl ------------------
-dnl Sets the gl_THREADLIB default so that threads are not used by default.
-dnl The user can still override it at installation time, by using the
-dnl configure option '--enable-threads'.
-
-AC_DEFUN([gl_DISABLE_THREADS], [
-  m4_divert_text([INIT_PREPARE], [gl_use_threads_default=no])
-])
-
-
-dnl Survey of platforms:
-dnl
-dnl Platform           Available  Compiler    Supports   test-lock
-dnl                    flavours   option      weak       result
-dnl ---------------    ---------  ---------   --------   ---------
-dnl Linux 2.4/glibc    posix      -lpthread       Y      OK
-dnl
-dnl GNU Hurd/glibc     posix
-dnl
-dnl FreeBSD 5.3        posix      -lc_r           Y
-dnl                    posix      -lkse ?         Y
-dnl                    posix      -lpthread ?     Y
-dnl                    posix      -lthr           Y
-dnl
-dnl FreeBSD 5.2        posix      -lc_r           Y
-dnl                    posix      -lkse           Y
-dnl                    posix      -lthr           Y
-dnl
-dnl FreeBSD 4.0,4.10   posix      -lc_r           Y      OK
-dnl
-dnl NetBSD 1.6         --
-dnl
-dnl OpenBSD 3.4        posix      -lpthread       Y      OK
-dnl
-dnl Mac OS X 10.[123]  posix      -lpthread       Y      OK
-dnl
-dnl Solaris 7,8,9      posix      -lpthread       Y      Sol 7,8: 0.0; Sol 9: OK
-dnl                    solaris    -lthread        Y      Sol 7,8: 0.0; Sol 9: OK
-dnl
-dnl HP-UX 11           posix      -lpthread       N (cc) OK
-dnl                                               Y (gcc)
-dnl
-dnl IRIX 6.5           posix      -lpthread       Y      0.5
-dnl
-dnl AIX 4.3,5.1        posix      -lpthread       N      AIX 4: 0.5; AIX 5: OK
-dnl
-dnl OSF/1 4.0,5.1      posix      -pthread (cc)   N      OK
-dnl                               -lpthread (gcc) Y
-dnl
-dnl Cygwin             posix      -lpthread       Y      OK
-dnl
-dnl Any of the above   pth        -lpth                  0.0
-dnl
-dnl Mingw              windows                    N      OK
-dnl
-dnl BeOS 5             --
-dnl
-dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
-dnl turned off:
-dnl   OK if all three tests terminate OK,
-dnl   0.5 if the first test terminates OK but the second one loops endlessly,
-dnl   0.0 if the first test already loops endlessly.