Modify the invocation of strace's "readlink" and "readlinkat" tests to prevent
them from failing due to an additional system call made by Guix's patched
version of glibc.
* gnu/packages/linux.scm (strace)[source]: Add patch.
[arguments]<#:phases>: Do not disable the "readlink" test now that it can
succeed.
* gnu/packages/patches/strace-readlink-tests.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
