--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
 2011-07-05  Paul Eggert  <eggert@cs.ucla.edu>
 
+	pthread_sigmask: new module
+	* MODULES.html.sh (Support for systems lacking POSIX:2008): Add it.
+	* doc/posix-functions/pthread_sigmask.texi: Document new module.
+	* lib/signal.in.h (pthread_sigmask): Arrange for replacement.
+	This is done only as a macro; I don't know how well that'll
+	work for C++.  Move <sys/types.h> include before the include_next,
+	to avoid mishap on Solaris.
+	* m4/signal_h.m4 (gl_SIGNAL_H, gl_SIGNAL_H_DEFAULTS): Check for it.
+	* modules/signal (Makefile.am): Substitute the check's results.
+	* modules/pthread_sigmask, m4/pthread_sigmask.m4: New files.
+
 	test-pselect: new module
 	* modules/pselect-tests, tests/test-pselect.c: New files.
 	* tests/test-select.c, tests/test-sys_select-c++.cc:

--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -2451,6 +2451,7 @@
   func_module times
   func_module timespec
   func_module nanosleep
+  func_module pthread_sigmask
   func_module regex
   func_module rename
   func_module renameat

--- a/doc/posix-functions/pthread_sigmask.texi
+++ b/doc/posix-functions/pthread_sigmask.texi
@@ -8,11 +8,14 @@
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function is missing on some platforms:
+Solaris 2.4, mingw, BeOS.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
 @item
-This function is missing on some platforms:
-Solaris 2.4, mingw, BeOS.
+On platforms that do not natively support this function,
+it has unspecified behavior in a multi-threaded process.
 @end itemize

--- a/lib/signal.in.h
+++ b/lib/signal.in.h
@@ -30,6 +30,12 @@
 
 #ifndef _@GUARD_PREFIX@_SIGNAL_H
 
+/* Define pid_t, uid_t.
+   Also, mingw defines sigset_t not in <signal.h>, but in <sys/types.h>.
+   On Solaris 10, <signal.h> includes <sys/types.h>, which eventually includes
+   us; so include <sys/types.h> now, before the second inclusion guard.  */
+#include <sys/types.h>
+
 /* The include_next requires a split double-inclusion guard.  */
 #@INCLUDE_NEXT@ @NEXT_SIGNAL_H@
 
@@ -42,10 +48,6 @@
 
 /* The definition of _GL_WARN_ON_USE is copied here.  */
 
-/* Define pid_t, uid_t.
-   Also, mingw defines sigset_t not in <signal.h>, but in <sys/types.h>.  */
-#include <sys/types.h>
-
 /* On AIX, sig_atomic_t already includes volatile.  C99 requires that
    'volatile sig_atomic_t' ignore the extra modifier, but C89 did not.
    Hence, redefine this to a non-volatile type as needed.  */
@@ -100,6 +102,20 @@
 #endif
 
 
+#if @GNULIB_PTHREAD_SIGMASK@
+# if @REPLACE_PTHREAD_SIGMASK@
+#  undef pthread_sigmask
+#  define pthread_sigmask sigprocmask
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef pthread_sigmask
+# if HAVE_RAW_DECL_PTHREAD_SIGMASK
+_GL_WARN_ON_USE (pthread_sigmask, "pthread_sigmask is not portable - "
+                 "use gnulib module pthread_sigmask for portability");
+# endif
+#endif
+
+
 #if @GNULIB_SIGPROCMASK@
 # if !@HAVE_POSIX_SIGNALBLOCKING@
 

new file mode 100644
--- /dev/null
+++ b/m4/pthread_sigmask.m4
@@ -0,0 +1,24 @@
+# pthread_sigmask.m4 serial 1
+dnl Copyright (C) 2011 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.
+
+AC_DEFUN([gl_PTHREAD_SIGMASK],
+[
+  m4_ifdef([gl_THREADLIB], [
+    AC_REQUIRE([gl_THREADLIB])
+    if test "$gl_threads_api" = posix; then
+      gl_save_LIBS="$LIBS"
+      LIBS="$LIBS $LIBMULTITHREAD"
+      AC_CHECK_FUNCS([pthread_sigmask])
+      LIBS="$gl_save_LIBS"
+    fi
+  ], [
+    AC_CHECK_FUNCS_ONCE([pthread_sigmask])
+  ])
+
+  if test $ac_cv_func_pthread_sigmask = no; then
+    REPLACE_PTHREAD_SIGMASK=0
+  fi
+])

--- a/m4/signal_h.m4
+++ b/m4/signal_h.m4
@@ -1,4 +1,4 @@
-# signal_h.m4 serial 12
+# signal_h.m4 serial 13
 dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -27,7 +27,8 @@
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[#include <signal.h>
-    ]], [sigaction sigaddset sigdelset sigemptyset sigfillset sigismember
+    ]], [pthread_sigmask sigaction
+    sigaddset sigdelset sigemptyset sigfillset sigismember
     sigpending sigprocmask])
 ])
 
@@ -42,6 +43,7 @@
 
 AC_DEFUN([gl_SIGNAL_H_DEFAULTS],
 [
+  GNULIB_PTHREAD_SIGMASK=0;    AC_SUBST([GNULIB_PTHREAD_SIGMASK])
   GNULIB_SIGNAL_H_SIGPIPE=0;   AC_SUBST([GNULIB_SIGNAL_H_SIGPIPE])
   GNULIB_SIGPROCMASK=0;        AC_SUBST([GNULIB_SIGPROCMASK])
   GNULIB_SIGACTION=0;          AC_SUBST([GNULIB_SIGACTION])
@@ -55,4 +57,5 @@
   HAVE_TYPE_VOLATILE_SIG_ATOMIC_T=1;
                                AC_SUBST([HAVE_TYPE_VOLATILE_SIG_ATOMIC_T])
   HAVE_SIGHANDLER_T=1;         AC_SUBST([HAVE_SIGHANDLER_T])
+  REPLACE_PTHREAD_SIGMASK=0;   AC_SUBST([REPLACE_PTHREAD_SIGMASK])
 ])

new file mode 100644
--- /dev/null
+++ b/modules/pthread_sigmask
@@ -0,0 +1,27 @@
+Description:
+POSIX compatible signal blocking for threads.
+
+Files:
+m4/pthread_sigmask.m4
+
+Depends-on:
+signal
+sigprocmask     [test $REPLACE_PTHREAD_SIGMASK = 1]
+
+configure.ac:
+gl_PTHREAD_SIGMASK
+gl_SYS_SELECT_MODULE_INDICATOR([pthread_sigmask])
+
+Makefile.am:
+
+Include:
+<signal.h>
+
+Link:
+$(LIBMULTITHREAD)
+
+License:
+LGPLv2+
+
+Maintainer:
+Paul Eggert, Bruno Haible, Jim Meyering

--- a/modules/signal
+++ b/modules/signal
@@ -28,6 +28,7 @@
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_SIGNAL_H''@|$(NEXT_SIGNAL_H)|g' \
+	      -e 's|@''GNULIB_PTHREAD_SIGMASK''@|$(GNULIB_PTHREAD_SIGMASK)|g' \
 	      -e 's/@''GNULIB_SIGNAL_H_SIGPIPE''@/$(GNULIB_SIGNAL_H_SIGPIPE)/g' \
 	      -e 's/@''GNULIB_SIGPROCMASK''@/$(GNULIB_SIGPROCMASK)/g' \
 	      -e 's/@''GNULIB_SIGACTION''@/$(GNULIB_SIGACTION)/g' \
@@ -38,6 +39,7 @@
 	      -e 's|@''HAVE_STRUCT_SIGACTION_SA_SIGACTION''@|$(HAVE_STRUCT_SIGACTION_SA_SIGACTION)|g' \
 	      -e 's|@''HAVE_TYPE_VOLATILE_SIG_ATOMIC_T''@|$(HAVE_TYPE_VOLATILE_SIG_ATOMIC_T)|g' \
 	      -e 's|@''HAVE_SIGHANDLER_T''@|$(HAVE_SIGHANDLER_T)|g' \
+	      -e 's|@''REPLACE_PTHREAD_SIGMASK''@|$(REPLACE_PTHREAD_SIGMASK)|g' \
 	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
 	      -e '/definition of _GL_ARG_NONNULL/r $(ARG_NONNULL_H)' \
 	      -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \