[binutils-gdb] Fix PR gdb/23558: Use system's 'getcwd' when cross-compiling GDB

[Sergio Durigan Junior <sergiodj at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e2fc52e745757a11f7a4a256984cabbe5474f55a

commit e2fc52e745757a11f7a4a256984cabbe5474f55a
Author: Sergio Durigan Junior <sergiodj@redhat.com>
Date:   Mon Sep 10 12:52:04 2018 -0400

    Fix PR gdb/23558: Use system's 'getcwd' when cross-compiling GDB
    
    This is a backport of a gnulib fix for the following bug:
    
      https://sourceware.org/bugzilla/show_bug.cgi?id=23558
    
    The problem reported there is about the replacement of 'getcwd' when
    cross-compiling GDB.  With our current gnulib copy, the mechanism for
    deciding whether to use the system's 'getcwd' or gnulib's version is
    too simplistic and pessimistic, so when cross-compiling we always end
    up using gnulib's version, which has a limitation: it cannot handle
    the situation when the parent directory doesn't have read permissions.
    
    The solution is to backport the following gnulib commit:
    
      commit a96d2e67052c879b1bcc5bc461722beac75fc372
      Author: Bruno Haible <bruno@clisp.org>
      Date:   Thu Aug 23 21:13:19 2018 +0200
    
          getcwd: Add cross-compilation guesses.
    
    gdb/ChangeLog:
    2018-09-10  Sergio Durigan Junior  <sergiodj@redhat.com>
    
    	PR gdb/23555
    	PR gdb/23558
    	* gnulib/import/m4/getcwd-path-max.m4: Add cross-compilation
    	guesses.

Diff:
---
 gdb/ChangeLog                           |  7 +++++++
 gdb/gnulib/import/m4/getcwd-path-max.m4 | 20 ++++++++++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b48b679..dc4346e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
 2018-09-10  Sergio Durigan Junior  <sergiodj@redhat.com>
 
+	PR gdb/23555
+	PR gdb/23558
+	* gnulib/import/m4/getcwd-path-max.m4: Add cross-compilation
+	guesses.
+
+2018-09-10  Sergio Durigan Junior  <sergiodj@redhat.com>
+
 	Revert:
 	2018-08-29  Sergio Durigan Junior  <sergiodj@redhat.com>
 
diff --git a/gdb/gnulib/import/m4/getcwd-path-max.m4 b/gdb/gnulib/import/m4/getcwd-path-max.m4
index 2531ccf..90bbc77 100644
--- a/gdb/gnulib/import/m4/getcwd-path-max.m4
+++ b/gdb/gnulib/import/m4/getcwd-path-max.m4
@@ -209,9 +209,21 @@ main ()
      32) gl_cv_func_getcwd_path_max='yes, but with shorter paths';;
      *) gl_cv_func_getcwd_path_max=no;;
      esac],
-    [case "$host_os" in
-       aix*) gl_cv_func_getcwd_path_max='no, it has the AIX bug';;
-       *) gl_cv_func_getcwd_path_max=no;;
-     esac])
+    [# Cross-compilation guesses:
+     case "$host_os" in
+       aix*) # On AIX, it has the AIX bug.
+         gl_cv_func_getcwd_path_max='no, it has the AIX bug' ;;
+       gnu*) # On Hurd, it is 'yes'.
+         gl_cv_func_getcwd_path_max=yes ;;
+       linux* | kfreebsd*)
+         # On older Linux+glibc it's 'no, but it is partly working',
+         # on newer Linux+glibc it's 'yes'.
+         # On Linux+musl libc, it's 'no, but it is partly working'.
+         # On kFreeBSD+glibc, it's 'no, but it is partly working'.
+         gl_cv_func_getcwd_path_max='no, but it is partly working' ;;
+       *) # If we don't know, assume the worst.
+         gl_cv_func_getcwd_path_max=no ;;
+     esac
+    ])
   ])
 ])