Backport pthreads.m4 from 1.2.

Both attributes.m4 and pthread.m4 are two reusable M4 macro files,
which can eaily be shared between different projects. For this reason
it's better if they are kept identical between branches.

1 files changed, 25 insertions, 0 deletions

diff --git a/m4/pthreads.m4 b/m4/pthreads.m4
index fb1adaab8..facac076f 100644
--- a/m4/pthreads.m4
+++ b/m4/pthreads.m4
@@ -73,3 +73,28 @@ AC_DEFUN([CC_PTHREAD_FLAGS], [
     ifelse([$2], , [:], [$2])
   fi
 ])
+
+AC_DEFUN([CC_PTHREAD_RECURSIVE_MUTEX], [
+    AC_REQUIRE([CC_PTHREAD_FLAGS])
+    AC_MSG_CHECKING([for recursive mutex support in pthread])
+
+    ac_save_LIBS="$LIBS"
+    LIBS="$LIBS $PTHREAD_LIBS"
+    AC_COMPILE_IFELSE(AC_LANG_SOURCE([#include <pthread.h>
+
+int main() {
+    pthread_mutexattr_t attr;
+    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+    return 0;
+}
+        ]), [have_recursive_mutex=yes], [have_recursive_mutex=no])
+    LIBS="$ac_save_LIBS"
+
+    AC_MSG_RESULT([$have_recursive_mutex])
+
+    if test x"$have_recursive_mutex" = x"yes"; then
+        ifelse([$1], , [:], [$1])
+    else
+        ifelse([$2], , [:], [$2])
+    fi
+])