diff --git a/ChangeLog b/ChangeLog
index d67fbfbea..f5020a233 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2003-01-30  Alexandre Oliva  <aoliva@redhat.com>
+
+	* config.if: Copy from GCC.
+
 2003-01-27  Phil Edwards  <pme@gcc.gnu.org>
 
 	* configure.in:  Revert 24Jan change.
diff --git a/config.if b/config.if
index 3958928ec..c38b59c84 100644
--- a/config.if
+++ b/config.if
@@ -2,9 +2,8 @@
 # Don't call it directly. This shell script fragment is called to
 # determine:
 #
-#	1. libstcxx_interface: the interface name for libstdc++.
-#	2. cxx_interface: the interface name for c++.
-#	3. libc_interface: the interface name for libc.
+#	1. libstcxx_incdir: the interface name for libstdc++.
+#	2. libc_interface: the interface name for libc.
 #
 
 # Get the top level src dir.
@@ -21,25 +20,21 @@ else
   if_topsrcdir=${top_srcdir}
 fi
 
-if [ "${enable_libstdcxx_v3}" = "yes" ] ; then
-  libstdcxx_srcdir=${if_topsrcdir}/libstdc++-v3
-else
-  libstdcxx_srcdir=${if_topsrcdir}/libstdc++
-fi
-
-if [ -f ${libstdcxx_srcdir}/Makefile.in ]; then
-# We check libstdc++ for libstdcxx_interface.
-libstdcxx_interface=`grep "^INTERFACE" ${libstdcxx_srcdir}/Makefile.in | sed 's/INTERFACE[ 	]*=[ 	]*\(.*\)/\1/'`
-else
-libstdcxx_interface=
-fi
-
-if [ -f ${if_topsrcdir}/gcc/cp/Makefile.in ]; then
-# We check gcc/cp for cxx_interface.
-cxx_interface=`grep "^INTERFACE" ${if_topsrcdir}/gcc/cp/Makefile.in | sed 's/INTERFACE[ 	]*=[ 	]*\(.*\)/\1/'`
-else
-cxx_interface=
+# Set libstdcxx_incdir.
+# This is the same as gcc/configure.in and libstdc++-v3/acinclude.m4. 
+if test -z "$gcc_version"; then
+  if test -z "${gcc_version_trigger}" \
+     && test -f ${if_topsrcdir}/gcc/version.c; then
+    gcc_version_trigger=${if_topsrcdir}/gcc/version.c
+  fi    
+  if test -f "${gcc_version_trigger}"; then
+    gcc_version_full=`grep version_string "${gcc_version_trigger}" | sed -e 's/.*"\([^"]*\)".*/\1/'`
+  else
+    gcc_version_full=`$CC -v 2>&1 | sed -n 's/^gcc version //p'`
+  fi
+  gcc_version=`echo ${gcc_version_full} | sed -e 's/\([^ ]*\) .*/\1/'`
 fi
+libstdcxx_incdir=c++/${gcc_version}
 
 # The trickiest part is libc_interface.
 if [ -z "${libc_interface}" ]
@@ -82,8 +77,8 @@ EOF
 	exit 1
       fi
     else
-      # Cross compiling. Assume glibc 2.2.
-      libc_interface=-libc6.2-
+      # Cross compiling. Assume glibc 2.1.
+      libc_interface=-libc6.1-
     fi
     ;;
   *)