Re: [PATCH 2/2] quilt: fix test for target build

[Qing He <qing.he@intel.com>]

On Wed, 2011-04-13 at 23:36 +0800, Khem Raj wrote:
> On Wed, Apr 13, 2011 at 2:26 AM, Qing He <qing.he@intel.com> wrote:
> > From: Qing He <qing.he@intel.com>
> >
> > fixes [YOCTO #969]
> >
> > Signed-off-by: Qing He <qing.he@intel.com>
> > ---
> > ??.../quilt/quilt/gnu_patch_test_fix_target.patch ?? ??| ?? 66 ++++++++++++++++++++
> > ??meta/recipes-devtools/quilt/quilt_0.48.bb ?? ?? ?? ?? ??| ?? ??6 +-
> > ??2 files changed, 70 insertions(+), 2 deletions(-)
> > ??create mode 100644 meta/recipes-devtools/quilt/quilt/gnu_patch_test_fix_target.patch
> >
> > diff --git a/meta/recipes-devtools/quilt/quilt/gnu_patch_test_fix_target.patch b/meta/recipes-devtools/quilt/quilt/gnu_patch_test_fix_target.patch
> > new file mode 100644
> > index 0000000..784fe76
> > --- /dev/null
> > +++ b/meta/recipes-devtools/quilt/quilt/gnu_patch_test_fix_target.patch
> > @@ -0,0 +1,66 @@
> > +The test of patch and diff should not be run for cross build,
> > +rather, assume them as gnu version is rather safe. This is a
> > +workaround to remove it altogether.
> > +
> 
> why is this patch needed. I assume all linux distributions use GNU
> diff and patch
> and that what is being checked so why remove the checks ? these messages
> are atleast useful for folks who are trying other build hosts e.g. darwin

Because patch is used at runtime rather than build time. It is used
mainly in patch-wrapper and some other scripts.

configure.ac of quilt practically doesn't differentiate them,
this leads to problems in cross-compiling:
  1. the QUILT_COMPAT_PROG_PATH finds the wrong patch, say we are
     building on darwin with a non-GNU patch, host patch found in
     /usr/bin or /sw/bin is irrelevant, what should be tested is
     <target sysroot>/path/to/patch(which may not be /usr/bin), and
     then @PATCH@ should be set to a value with <target sysroot>
     removed.
  2. the test is performed by running "patch --version", this obviously
     doesn't work for cross-compiling.

The right way to do this may be something like:
  if test "x$cross_compiling" = "xyes"; then
    AC_CHECK_PROG in target sysroot
    PATCH=strip sysroot in the absolute path
  else
    QUILT_COPAT_PROG_PATH
    original test
  fi

This is troublesome and error prone, since a separate SYSROOT needs to
be handled by configure, and target patch may as well not in a standard
path. The simplest way to do it is to remove the test, as we have
separate recipes for quilt and quilt-native.


The reason to touch this part of code is that the test itself doesn't
work for newer versions of GNU patch, see:
  http://lists.nongnu.org/archive/html/quilt-dev/2010-06/msg00002.html
This surely fixes the configure error, but is logically not suitable for
cross compiling.

Thanks,
Qing