Re: [PATCH] Crosscompiling configure fix

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Feb  5 21:34, Peter Foley wrote:
> I've submitted a fix for a problem I came across while trying to build a Linux-hosted Cygwin cross compiler. While bootstrapping Cygwin the autoconf scripts in winsup/cygwin and winsup/cygserver fail because the bootstrap compiler is missing some of the files needed to link a Cygwin executable. Because the source for some of the needed files is in the winsup directory, this creates a curricular dependency. The attached patch lets autoconf complete successfully by not running the tests that require linking if Cygwin is being crosscompiled.
> 
> Thanks,
> 
> Peter Foley
> 
> winsup/cygserver/ChangeLog:
> 
> 2011-02-5 Peter Foley <...>
> 
> 	* configure.in: Skip tests that require linking if cross compiling.
> 	* configure: Regenerate.
> 
> winsup/cygwin/ChangeLog:
> 
> 2011-02-5 Peter Foley <...>
> 
> 	* configure.in: Skip tests that require linking if cross compiling.
> 	* configure: Regenerate.

Thanks for the patch.  Btw., you don't have to provide the generated
files, the configure.in files are sufficient.

I'm just wondering why we need this stuff at all.  I mean, is there
really any good reason to do the AC_ALLOCA test, and why do we have
this AC_TRY_COMPILE test for __builtin_memset?  Both results are not
used anywhere, they are just written to config.h and then forgotten.

So I take it, we could just drop this stuff.

Chris?  What do you say?

Index: cygserver/configure.in
===================================================================
RCS file: /cvs/src/src/winsup/cygserver/configure.in,v
retrieving revision 1.4
diff -u -p -r1.4 configure.in
--- cygserver/configure.in	24 May 2006 16:59:02 -0000	1.4
+++ cygserver/configure.in	7 Feb 2011 11:57:29 -0000
@@ -44,26 +44,8 @@ AC_CHECK_TOOL(NM, nm, nm)
 AC_CHECK_TOOL(DLLTOOL, dlltool, dlltool)
 AC_CHECK_TOOL(WINDRES, windres, windres)
 
-AC_ALLOCA
 AC_PROG_MAKE_SET
 
-dnl check whether gcc supports __builtin_memset.
-# Test for builtin mem* functions.
-AC_LANG_SAVE
-AC_LANG_CPLUSPLUS
-AC_TRY_COMPILE([
-#include <string.h>
-void foo(char *s, int c, size_t n)
-{
-  __builtin_memset(s, c, n);
-}
-], [ ],
-use_builtin_memset=yes, use_builtin_memset=no)
-if test $use_builtin_memset = "yes"; then
-  AC_DEFINE(HAVE_BUILTIN_MEMSET)
-fi
-AC_LANG_RESTORE
-
 AC_ARG_ENABLE(debugging,
 [ --enable-debugging		Build a cygwin DLL which has more consistency checking for debugging],
 [case "${enableval}" in
Index: cygwin/configure.in
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/configure.in,v
retrieving revision 1.34
diff -u -p -r1.34 configure.in
--- cygwin/configure.in	29 Jan 2011 06:41:28 -0000	1.34
+++ cygwin/configure.in	7 Feb 2011 11:57:29 -0000
@@ -48,26 +48,8 @@ AC_CHECK_TOOL(RANLIB, ranlib, ranlib)
 AC_CHECK_TOOL(STRIP, strip, strip)
 AC_CHECK_TOOL(WINDRES, windres, windres)
 
-AC_ALLOCA
 AC_PROG_MAKE_SET
 
-dnl check whether gcc supports __builtin_memset.
-# Test for builtin mem* functions.
-AC_LANG_SAVE
-AC_LANG_CPLUSPLUS
-AC_TRY_COMPILE([
-#include <string.h>
-void foo(char *s, int c, size_t n)
-{
-  __builtin_memset(s, c, n);
-}
-], [ ],
-use_builtin_memset=yes, use_builtin_memset=no)
-if test $use_builtin_memset = "yes"; then
-  AC_DEFINE(HAVE_BUILTIN_MEMSET)
-fi
-AC_LANG_RESTORE
-
 AC_ARG_ENABLE(debugging,
 [ --enable-debugging		Build a cygwin DLL which has more consistency checking for debugging],
 [case "${enableval}" in

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat