diff --git a/config/ompi_config_threads.m4 b/config/ompi_config_threads.m4
index 5031757b59..7c3b7f3865 100644
--- a/config/ompi_config_threads.m4
+++ b/config/ompi_config_threads.m4
@@ -171,8 +171,8 @@ EOF
     fi
 fi
 
-AM_CONDITIONAL(OMPI_HAVE_POSIX_THREADS, test "$thread_type" = "posix")
-AM_CONDITIONAL(OMPI_HAVE_SOLARIS_THREADS, test "$thread_type" = "solaris")
+AM_CONDITIONAL(OMPI_HAVE_POSIX_THREADS, test "$THREAD_TYPE" = "posix")
+AM_CONDITIONAL(OMPI_HAVE_SOLARIS_THREADS, test "$THREAD_TYPE" = "solaris")
 
 #
 # Now configure the whole MPI and progress thread gorp
diff --git a/opal/mca/memory/ptmalloc2/Makefile.am b/opal/mca/memory/ptmalloc2/Makefile.am
index ca1ba4da49..21ec06041e 100644
--- a/opal/mca/memory/ptmalloc2/Makefile.am
+++ b/opal/mca/memory/ptmalloc2/Makefile.am
@@ -21,7 +21,10 @@
 AM_CPPFLAGS = -DMALLOC_DEBUG=0
 
 if OMPI_HAVE_POSIX_THREADS
-AM_CPPFLAGS +=  -DUSE_TSD_DATA_HACK \
+AM_CPPFLAGS +=  \
+    -D_GNU_SOURCE=1 \
+    -DUSE_TSD_DATA_HACK=1 \
+    -DMALLOC_HOOKS=1 \
     -I$(srcdir)/sysdeps/pthread
 endif
 if OMPI_HAVE_SOLARIS_THREADS
diff --git a/opal/mca/memory/ptmalloc2/sysdeps/pthread/malloc-machine.h b/opal/mca/memory/ptmalloc2/sysdeps/pthread/malloc-machine.h
index 3940a7d6f9..401202ad69 100644
--- a/opal/mca/memory/ptmalloc2/sysdeps/pthread/malloc-machine.h
+++ b/opal/mca/memory/ptmalloc2/sysdeps/pthread/malloc-machine.h
@@ -78,7 +78,7 @@ static inline int mutex_trylock(mutex_t *m) {
 }
 static inline int mutex_unlock(mutex_t *m) {
   m->lock = 0;
-  __asm __volatile ("" : "=m" (m->lock) : "0" (m->lock));
+  __asm __volatile ("" : : : "memory");
   return 0;
 }