Here's my proposed patch, along the lines you suggested. top_srcdir
didn't seem to be set, so I used srcdir instead.
Bootstrapped on x86_64-unknown-linux-gnu
2011-06-04 Douglas B Rupp <r...@gnat.com>
* fixincludes/configure.ac (host_makefile_frag): Use mh-interix.
* fixincludes/configure: Regenerate
* fixincludes/Makefile.in (FIXINC_CPPFLAGS): New flag macro.
(@host_makefile_frag@): New substitution placeholder.
(.c.o): Use FIXINC_CPPFLAGS.
diff -rupN gcc.orig/fixincludes/configure.ac gcc/fixincludes/configure.ac
--- gcc.orig/fixincludes/configure.ac 2011-04-06 17:01:09.000000000 -0700
+++ gcc/fixincludes/configure.ac 2011-06-04 13:18:23.000000000 -0700
@@ -23,6 +23,20 @@ ACX_PROG_CC_WARNINGS_ARE_ERRORS([manual]
# Determine the noncanonical target name, for directory use.
ACX_NONCANONICAL_TARGET
+host_makefile_frag=/dev/null
+if test -d ${srcdir}/../config ; then
+case "${host}" in
+ *-interix[[3-9]]*)
+ host_makefile_frag="config/mh-interix"
+ ;;
+esac
+fi
+
+if test $host_makefile_frag != /dev/null; then
+ eval host_makefile_frag=${srcdir}/../$host_makefile_frag
+fi
+AC_SUBST_FILE(host_makefile_frag)
+
# Specify the local prefix
local_prefix=
AC_ARG_WITH(local-prefix,
diff -rupN gcc.orig/fixincludes/Makefile.in gcc/fixincludes/Makefile.in
--- gcc.orig/fixincludes/Makefile.in 2011-04-06 17:01:09.000000000 -0700
+++ gcc/fixincludes/Makefile.in 2011-06-04 00:31:30.000000000 -0700
@@ -32,6 +32,11 @@ WARN_CFLAGS = @WARN_CFLAGS@ @WARN_PEDANT
LDFLAGS = @LDFLAGS@
INCLUDES = -I. -I$(srcdir) -I../include -I$(srcdir)/../include
FIXINC_CFLAGS = -DHAVE_CONFIG_H $(INCLUDES)
+FIXINC_CPPFLAGS =
+
+#### host specific makefile fragments come in here.
+@host_makefile_frag@
+###
# Directory where sources are, from where we are.
srcdir = @srcdir@
@@ -73,7 +78,7 @@ default : all
# Now figure out from those variables how to compile and link.
.c.o:
- $(CC) -c $(CFLAGS) $(WARN_CFLAGS) $(CPPFLAGS) $(FIXINC_CFLAGS) $<
+ $(CC) -c $(CFLAGS) $(WARN_CFLAGS) $(CPPFLAGS) $(FIXINC_CPPFLAGS)
$(FIXINC_CFLAGS) $<
# The only suffixes we want for implicit rules are .c and .o.
.SUFFIXES:
