--- gcc-4.1.0/gcc/Makefile.in.old
+++ gcc-4.1.0/gcc/Makefile.in
@@ -388,7 +388,10 @@
 CROSS_SYSTEM_HEADER_DIR = @CROSS_SYSTEM_HEADER_DIR@

 # autoconf sets SYSTEM_HEADER_DIR to one of the above.
-SYSTEM_HEADER_DIR = @SYSTEM_HEADER_DIR@
+# Purge it of unneccessary internal relative paths
+# to directories that might not exist yet.
+# The sed idiom for this is to repeat the search-and-replace until it doesn't match, using :a ... ta.
+SYSTEM_HEADER_DIR = `echo @SYSTEM_HEADER_DIR@ | sed -e :a -e "s,[^/]*/\.\.\/,," -e ta`

 # Control whether to run fixproto and fixincludes.
 STMP_FIXPROTO = @STMP_FIXPROTO@
@@ -3173,7 +3176,7 @@
 	@if ! $(inhibit_libc) && test ! -d ${SYSTEM_HEADER_DIR}; then \
 	  echo The directory that should contain system headers does not exist: >&2 ; \
 	  echo "  ${SYSTEM_HEADER_DIR}" >&2 ; \
-	  if test "x${SYSTEM_HEADER_DIR}" = "x${gcc_tooldir}/sys-include"; \
+         if test "x${SYSTEM_HEADER_DIR}" = "x`echo "${gcc_tooldir}/sys-include" | sed -e :a -e "s,[^/]*/\.\.\/,," -e ta`"; \
 	  then sleep 1; else exit 1; fi; \
 	fi
 	rm -rf include; mkdir include