Index: gcc/testsuite/lib/plugin-support.exp
===================================================================
--- gcc/testsuite/lib/plugin-support.exp	(revision 164915)
+++ gcc/testsuite/lib/plugin-support.exp	(working copy)
@@ -88,6 +88,10 @@
 
     set optstr "$includes $extra_flags -DIN_GCC -fPIC -shared"
 
+    if { [ ishost *-*-darwin* ] } {
+	set optstr [concat $optstr "-undefined dynamic_lookup"]
+    }
+
     # Temporarily switch to the environment for the plugin compiler.
     restore_ld_library_path_env_vars
     set status [remote_exec build "$PLUGINCC $PLUGINCFLAGS $plugin_src $optstr -o $plugin_lib"]
Index: gcc/configure.ac
===================================================================
--- gcc/configure.ac	(revision 164915)
+++ gcc/configure.ac	(working copy)
@@ -4543,13 +4543,26 @@
 
 pluginlibs=
 
-if test x$build = x$host; then
-  export_sym_check="objdump${exeext} -T"
-elif test x$host = x$target; then
-  export_sym_check="$gcc_cv_objdump -T"
-else
-  export_sym_check=
-fi
+case "${host}" in
+  *-*-darwin*)
+    if test x$build = x$host; then
+      export_sym_check="nm${exeext} -g"
+    elif test x$host = x$target; then
+      export_sym_check="$gcc_cv_nm -g"
+    else
+      export_sym_check=
+    fi
+  ;;
+  *)
+    if test x$build = x$host; then
+      export_sym_check="objdump${exeext} -T"
+    elif test x$host = x$target; then
+      export_sym_check="$gcc_cv_objdump -T"
+    else
+      export_sym_check=
+    fi
+  ;;
+esac
 
 if test x"$enable_plugin" = x"yes"; then
 
@@ -4587,7 +4600,14 @@
 
   # 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;],