diff --git a/ChangeLog b/ChangeLog
index 79faa94372..42b02ee218 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2013-05-15  Peter Collingbourne  <pcc@google.com>
+
+	* malloc/obstack.c (_obstack_compat): Add initializer.
+
 2013-05-15  Edjunior Machado  <emachado@linux.vnet.ibm.com>
 
 	* sysdeps/unix/sysv/linux/s390/bits/siginfo.h (siginfo_t): Remove
diff --git a/malloc/obstack.c b/malloc/obstack.c
index 25a90514f7..c3c7db4a96 100644
--- a/malloc/obstack.c
+++ b/malloc/obstack.c
@@ -115,7 +115,7 @@ int obstack_exit_failure = EXIT_FAILURE;
 /* A looong time ago (before 1994, anyway; we're not sure) this global variable
    was used by non-GNU-C macros to avoid multiple evaluation.  The GNU C
    library still exports it because somebody might use it.  */
-struct obstack *_obstack_compat;
+struct obstack *_obstack_compat = 0;
 compat_symbol (libc, _obstack_compat, _obstack, GLIBC_2_0);
 #  endif
 # endif