Index: gcc/configure.ac
===================================================================
--- gcc/configure.ac	(revision 161355)
+++ gcc/configure.ac	(working copy)
@@ -4544,15 +4544,23 @@
 pluginlibs=
 if test x"$enable_plugin" = x"yes"; then
 
+  case "${host}" in
+    *-*-darwin*)
+      export_sym_check="$gcc_cv_nm -g"
+    ;;
+    *)
+      export_sym_check="$gcc_cv_objdump -T"
+    ;;
+  esac
   AC_MSG_CHECKING([for exported symbols])
   echo "int main() {return 0;} int foobar() {return 0;}" > conftest.c
   ${CC} ${CFLAGS} ${LDFLAGS} conftest.c -o conftest > /dev/null 2>&1
-  if $gcc_cv_objdump -T conftest | grep foobar > /dev/null; then
+  if $export_sym_check conftest | grep foobar > /dev/null; then
     : # No need to use a flag
   else
     AC_MSG_CHECKING([for -rdynamic])
     ${CC} ${CFLAGS} ${LDFLAGS} -rdynamic conftest.c -o conftest > /dev/null 2>&1
-    if $gcc_cv_objdump -T conftest | grep foobar > /dev/null; then
+    if $export_sym_check conftest | grep foobar > /dev/null; then
       plugin_rdynamic=yes
       pluginlibs="-rdynamic"
     else
@@ -4572,7 +4580,14 @@
 
   # Check that we can build shared objects with -fPIC -shared
   saved_LDFLAGS="$LDFLAGS"
-  LDFLAGS="$LDFLAGS -fPIC -shared"
+  case "${host}" in
+    *-*-darwin*)
+      LDFLAGS="$LDFLAGS -fPIC -shared -undefined dynamic_lookup"
+    ;;
+    *)
+      LDFLAGS="$LDFLAGS -fPIC -shared"
+    ;;
+  esac
   AC_MSG_CHECKING([for -fPIC -shared])
   AC_TRY_LINK(
     [extern int X;],[return X == 0;],