diff -upr libstdcxx-orig/libstdcxx/libstdc++-v3/acinclude.m4 libstdc++-v3/acinclude.m4
--- libstdcxx-orig/libstdcxx/libstdc++-v3/acinclude.m4	2005-08-03 10:39:07.000000000 -0700
+++ libstdc++-v3/acinclude.m4	2005-08-03 14:45:02.000000000 -0700
@@ -626,13 +626,13 @@ dnl Substs:
 dnl  baseline_dir
 dnl
 AC_DEFUN([GLIBCXX_CONFIGURE_TESTSUITE], [
-  if $GLIBCXX_IS_NATIVE && test $is_hosted = yes; then
-    # Do checks for resource limit functions.
-    GLIBCXX_CHECK_SETRLIMIT
+  # Do checks for resource limit functions.
+  GLIBCXX_CHECK_SETRLIMIT
 
-    # Look for setenv, so that extended locale tests can be performed.
-    GLIBCXX_CHECK_STDLIB_DECL_AND_LINKAGE_3(setenv)
+  # Look for setenv, so that extended locale tests can be performed.
+  GLIBCXX_CHECK_STDLIB_DECL_AND_LINKAGE_3(setenv)
 
+  if $GLIBCXX_IS_NATIVE && test $is_hosted = yes; then
     if test $enable_symvers = no; then
       enable_abi_check=no
     else
diff -upr libstdcxx-orig/libstdcxx/libstdc++-v3/configure libstdc++-v3/configure
--- libstdcxx-orig/libstdcxx/libstdc++-v3/configure	2005-08-03 10:39:07.000000000 -0700
+++ libstdc++-v3/configure	2005-08-03 14:45:58.000000000 -0700
@@ -1542,7 +1542,24 @@ target_alias=${target_alias-$host_alias}
 if test "$build" != "$host"; then
   # We are being configured with some form of cross compiler.
   GLIBCXX_IS_NATIVE=false
+  case "$host","$target" in
+    # Darwin crosses can use the host system's libraries and headers,
+    # because of the fat library support.  Of course, it must be the
+    # same version of Darwin on both sides.  Allow the user to
+    # just say --target=foo-darwin without a version number to mean
+    # "the version on this system".
+      *-*-darwin*,*-*-darwin*)
+	hostos=`echo $host | sed 's/.*-darwin/darwin/'`
+	targetos=`echo $target | sed 's/.*-darwin/darwin/'`
+	if test $hostos = $targetos -o $targetos = darwin ; then
+	  GLIBCXX_IS_NATIVE=true
+	fi
+	;;
+
+      *)
 
+	;;
+  esac
 else
   GLIBCXX_IS_NATIVE=true
 fi
@@ -4390,7 +4407,7 @@ test x"$pic_mode" = xno && libtool_flags
 case $host in
 *-*-irix6*)
   # Find out which ABI we are using.
-  echo '#line 4393 "configure"' > conftest.$ac_ext
+  echo '#line 4410 "configure"' > conftest.$ac_ext
   if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   (eval $ac_compile) 2>&5
   ac_status=$?
@@ -5011,7 +5028,7 @@ fi;
     #
     # Fake what AC_TRY_COMPILE does.  XXX Look at redoing this new-style.
     cat > conftest.$ac_ext << EOF
-#line 5014 "configure"
+#line 5031 "configure"
 struct S { ~S(); };
 void bar();
 void foo()
@@ -98357,8 +98374,7 @@ echo "$as_me: versioning on shared libra
 
 # This depends on GLIBCXX_ENABLE_SYMVERS and GLIBCXX_IS_NATIVE.
 
-  if $GLIBCXX_IS_NATIVE && test $is_hosted = yes; then
-    # Do checks for resource limit functions.
+  # Do checks for resource limit functions.
 
   setrlimit_have_headers=yes
 
@@ -98869,7 +98885,7 @@ _ACEOF
 echo "${ECHO_T}$ac_res_limits" >&6
 
 
-    # Look for setenv, so that extended locale tests can be performed.
+  # Look for setenv, so that extended locale tests can be performed.
 
   echo "$as_me:$LINENO: checking for setenv declaration" >&5
 echo $ECHO_N "checking for setenv declaration... $ECHO_C" >&6
@@ -99054,6 +99070,7 @@ done
   fi
 
 
+  if $GLIBCXX_IS_NATIVE && test $is_hosted = yes; then
     if test $enable_symvers = no; then
       enable_abi_check=no
     else
diff -upr libstdcxx-orig/libstdcxx/libstdc++-v3/configure.ac libstdc++-v3/configure.ac
--- libstdcxx-orig/libstdcxx/libstdc++-v3/configure.ac	2005-01-03 13:31:33.000000000 -0800
+++ libstdc++-v3/configure.ac	2005-08-03 14:44:28.000000000 -0700
@@ -42,7 +42,24 @@ target_alias=${target_alias-$host_alias}
 if test "$build" != "$host"; then
   # We are being configured with some form of cross compiler.
   GLIBCXX_IS_NATIVE=false
-  GCC_NO_EXECUTABLES
+  case "$host","$target" in
+    # Darwin crosses can use the host system's libraries and headers,
+    # because of the fat library support.  Of course, it must be the
+    # same version of Darwin on both sides.  Allow the user to
+    # just say --target=foo-darwin without a version number to mean
+    # "the version on this system".
+      *-*-darwin*,*-*-darwin*)
+	hostos=`echo $host | sed 's/.*-darwin/darwin/'`
+	targetos=`echo $target | sed 's/.*-darwin/darwin/'`
+	if test $hostos = $targetos -o $targetos = darwin ; then
+	  GLIBCXX_IS_NATIVE=true
+	fi
+	;;
+
+      *)
+	GCC_NO_EXECUTABLES
+	;;
+  esac
 else
   GLIBCXX_IS_NATIVE=true
 fi