--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2014-06-14  Paul Eggert  <eggert@cs.ucla.edu>
+
+	pthread: don't assume AC_CANONICAL_HOST, port better to Solaris, etc.
+	* modules/pthread (Depends-on): Add 'extensions', as it defines
+	_POSIX_PTHREAD_SEMANTICS, which is needed on Solaris.
+	(configure.ac-early): New section.
+	* m4/pthread.m4 (gl_PTHREAD_CHECK): Revert previous change, as
+	it is no longer needed.
+
 2014-06-14  Pádraig Brady  <P@draigBrady.com>
 
 	pthread: define thread-safe macros on some platforms

--- a/m4/pthread.m4
+++ b/m4/pthread.m4
@@ -88,20 +88,6 @@
    fi
    AC_SUBST([LIB_PTHREAD])
 
-   dnl Some systems optimize for single-threaded programs by default, and
-   dnl need special flags to disable these optimizations. For example, the
-   dnl definition of 'errno' in <errno.h>.
-   case "$host_os" in
-     aix* | freebsd*)
-       AC_DEFINE([_THREAD_SAFE], 1,
-         [Define on some systems, to enable only thread-safe operations.])
-     ;;
-     osf* | solaris*)
-       AC_DEFINE([_REENTRANT], 1,
-         [Define on some systems, to enable only thread-safe operations.])
-     ;;
-   esac
-
    AC_REQUIRE([AC_C_RESTRICT])
 ])
 

--- a/modules/pthread
+++ b/modules/pthread
@@ -7,10 +7,15 @@
 m4/pthread.m4
 
 Depends-on:
+extensions
 extern-inline
 sched
 time
 
+configure.ac-early:
+AC_DEFINE([_REENTRANT], 1, [For thread-safety on OSF/1, Solaris.])
+AC_DEFINE([_THREAD_SAFE], 1, [For thread-safety on AIX, FreeBSD.])
+
 configure.ac:
 gl_PTHREAD_CHECK
 gl_MODULE_INDICATOR([pthread])