[newlib-cygwin] Fix multilib libgloss selection.

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=332a6236a2f3d6b15523b10b7da3685b1c79f65d

commit 332a6236a2f3d6b15523b10b7da3685b1c79f65d
Author: Marcus Shawcroft <marcus.shawcroft@arm.com>
Date:   Fri Nov 6 14:41:33 2015 +0000

    Fix multilib libgloss selection.
    
    Regression testing newlib in conjunction with libgloss and
    --enable-multilib can result in incompatible multilib versions of
    newlib and libgloss being used during link.
    
    This manifests on ARM target when newlib regression is run using a
    GCC configured using --with-multilib-list=aprofile
    
    With this configuration many of the multilib variants built are
    mutually incompatible.
    
    The issue is that the newlib dejagnu foo iterates each multilib
    variant and correctly chooses the appropriate newlib variant but
    always chooses the root/base libgloss variant.
    
    The implementation of newlib/testsuite/lib/flags.exp contains the
    following fragment:
    
    set target_build_path "$objdir/$multibuildtop.."
    
    The effect of this fragment is to explicitly select the root version
    of libgloss, irrespective of the current multilib.
    
    Digging around in VC it appears that the original implementation of
    multlib magic came into the tree back in 2002 with:
    
    6e9d950a (Thomas Fitzsimmons 2002-05-01 17:06:25 +0000 39)
    
    In this initial version of multilib support, newlib was multilib
    capable, but libgloss was not multilib capable, hence the necessity to
    explicitly select the root libgloss version.
    
    Subsequently flags.exp was modified to support out of tree testing:
    
    cec1d3b4 (Jeff Johnston      2005-07-05 00:11:50 +0000 25)
    
    This change is orthogonal to this issue, its effect is to exit early
    in none multilib configurations.
    
    Subsequently libgloss gained --enable-multilib support, the relevant
    change is:
    
    https://sourceware.org/ml/newlib/2006/msg00440.html
    commit 00a4b31ad08aef361c5d74125ece410b4c285975
    Author: Jeff Johnston <jjohnstn@redhat.com>
    Date: Wed May 10 20:51:41 2006 +0000
    
    This change enabled multilib support throughout libgloss, but ommitted
    to adjust the flag.exp behaviour which anchors the libgloss multilib
    selection to the base version.
    
    The attached patch adjusts flags.exp to select the current multilib
    variant of libgloss.
    
    2015-11-06  Marcus Shawcroft  <marcus.shawcroft@arm.com>
    
            * testsuite/lib/flags.exp (libgloss_link_flags): Drop multilibtop
            from target_build_path.

Diff:
---
 newlib/ChangeLog               | 5 +++++
 newlib/testsuite/lib/flags.exp | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/newlib/ChangeLog b/newlib/ChangeLog
index bc0ec24..b034f57 100644
--- a/newlib/ChangeLog
+++ b/newlib/ChangeLog
@@ -1,3 +1,8 @@
+2015-11-12  Marcus Shawcroft  <marcus.shawcroft@arm.com>
+
+	* testsuite/lib/flags.exp (libgloss_link_flags): Drop multilibtop
+	from target_build_path.
+
 2015-11-06  Jon Turney  <jon.turney@dronecode.org.uk>
 
 	* doc/makedoc.c (iscommand): Only allow commands to have trailing
diff --git a/newlib/testsuite/lib/flags.exp b/newlib/testsuite/lib/flags.exp
index 577efa8..e1e9acb 100644
--- a/newlib/testsuite/lib/flags.exp
+++ b/newlib/testsuite/lib/flags.exp
@@ -36,7 +36,7 @@ proc libgloss_link_flags { args } {
 	return ""
     }
 
-    set target_build_path "$objdir/$multibuildtop.."
+    set target_build_path "$objdir/.."
 
     set gloss_srcdir [lookfor_file ${srcdir} libgloss/$target_cpu]