diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 490f7d5f574..3b16284da60 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2012-01-17  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
+	PR target/47852
+	* configure.host (irix6.5*): Add -lpthread to OPT_LDFLAGS.
+
 2012-01-14  Jonathan Wakely  <jwakely.gcc@gmail.com>
 
 	* include/bits/stl_iterator.h (reverse_iterator): Doxygen comments.
diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
index 4da4508fa4f..715d549546f 100644
--- a/libstdc++-v3/configure.host
+++ b/libstdc++-v3/configure.host
@@ -258,6 +258,10 @@ case "${host_os}" in
     os_include_dir="os/irix/irix6.5"
     atomicity_dir=os/irix
     atomic_word_dir=os/irix
+    # libstdc++.so relies on emutls on IRIX, which only works with the
+    # real functions implemented in libpthread.so, not with the stubs in
+    # libc, so always pass -lpthread.
+    OPT_LDFLAGS="${OPT_LDFLAGS} -lpthread"
     ;;
   mingw32*)
     case "$host" in