[newlib-cygwin] newlib: fix cygwin -I path

[Michael Frysinger <vapier@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=6a59fc444b46681b59ce3152cfbd3c9e024455fa

commit 6a59fc444b46681b59ce3152cfbd3c9e024455fa
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Thu Jan 27 19:29:14 2022 -0500

    newlib: fix cygwin -I path
    
    This code snippet assumed it was only ever run in the top configure
    script where srcdir would point to newlib/ which is parallel to the
    winsup/ tree.  This is incorrect for all of the subdir configure
    scripts leading to bad -I flags in $(CC).  Switch it over to the
    new abs_newlib_basedir which should work in all subdirs.

Diff:
---
 newlib/configure.host | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/newlib/configure.host b/newlib/configure.host
index ca6b46f03..bf4a555e6 100644
--- a/newlib/configure.host
+++ b/newlib/configure.host
@@ -641,7 +641,7 @@ esac
 
 case "${host}" in
   *-*-cygwin*)
-	test -z "$cygwin_srcdir" && cygwin_srcdir=`cd ${srcdir}/../winsup/cygwin; pwd`
+	test -z "$cygwin_srcdir" && cygwin_srcdir="${abs_newlib_basedir}/../winsup/cygwin"
 	export cygwin_srcdir
 	default_newlib_io_c99_formats="yes"
 	default_newlib_io_long_long="yes"