This change allows overriding the home directory of all filesystem mappings to
help hide the identity of the calling user in a container.

* doc/guix.texi (Invoking guix environment)[--container]: Mention --user.
[--user]: Add item.
* guix/scripts/environment.scm (show-help): Add --user.
(%options): Add --user.
(launch-environment/container) Add 'user' parameter.  Update doc.  Override
'user-mappings' using 'override-user-mappings'.  Consider override for chdir.
(mock-passwd, user-override-home, overrid-euser-dir): New procedures.
(guix-environment): Disallow --user without --container.  Provide user to
'launch-environment/container'.
* tests/guix-environment.sh: Add user test.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

This change is motivated by attempts to run programs (like GNU IceCat) within
containers.  The 'fontconfig' program, for example, is configured explicitly
to check ~/.guix-profile for additional fonts.

There were no existing container tests in 'tests/guix-environment.sh', but I
added one anyway for this change.

* doc/guix.texi (Invoking guix environment): Add '--link-profile'.
* guix/scripts/environment.scm (show-help): Add '--link-profile'.
(%options): Add 'link-profile' as '#\P', assigned to 'link-profile?'.
(link-environment): New procedure.
(launch-environment/container): Use it when 'link-profile?'.
[link-profile?]: New parameter.
(guix-environment): Leave when '--link-prof' but not '--container'.  Add
'#:link-profile?' argument to 'launch-environment/container' application.
* tests/guix-environment-container.sh: New '--link-profile' test.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

* gnu/packages/gnuzilla.scm (icecat)[source]: Add selected fixes from the
upstream mozilla-esr52 repository.

* gnu/packages/gnuzilla.scm (icecat): Update to 52.6.0-gnu1.
[source]: Remove patches that are no longer needed.
* gnu/packages/patches/icecat-bug-1348660-pt5.patch,
gnu/packages/patches/icecat-bug-1414945.patch,
gnu/packages/patches/icecat-bug-1415133.patch,
gnu/packages/patches/icecat-bug-1424373-pt2.patch: Delete files.
* gnu/local.mk (dist_patch_DATA): Remove them.

* gnu/packages/databases.scm (postgresql-9.6): Update to 9.6.8.

* gnu/packages/databases.scm (postgresql): Update to 10.3.

* gnu/packages/databases.scm (memcached): Update to 1.5.6.

* gnu/packages/linux.scm (%linux-libre-version): Update to 4.15.7.
(%linux-libre-hash): Update hash.

* gnu/packages/linux.scm (%linux-libre-4.14-version): Update to 4.14.23.
(%linux-libre-4.14-hash): Update hash.

* gnu/packages/linux.scm (linux-libre-4.9): Update to 4.9.85.

* gnu/packages/linux.scm (linux-libre-4.4): Update to 4.4.119.

* gnu/packages/php.scm (php)[inputs]: Use gd-for-php.
(gd-for-php): New private variable.
* gnu/packages/patches/gd-CVE-2018-5711.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.

* gnu/packages/sdcc.scm (sdcc)[description]: Fix (upstream) typo.  Add
hyphens.

* gnu/packages/sdcc.scm (sdcc): Update to 3.7.0.

* gnu/packages/php.scm (php): Update to 7.2.3.

* gnu/packages/python.scm (python-stem): Update to 1.6.0.
[arguments]: Add ‘fix-test-environment’ phase.

* gnu/packages/tor.scm (onionshare)[arguments]: Substitute INVOKE for
SYSTEM* and end phase with #t.

* gnu/packages/tor.scm (privoxy)[arguments]: Substitute INVOKE for
SYSTEM* and end phase with #t.

* gnu/packages/python.scm (python-stem)[arguments]: Substitute INVOKE
for SYSTEM* and end phase with #t.

* gnu/packages/audio.scm (liblo): Update to 0.29.

* gnu/packages/monitoring.scm (nagios): Update to 4.3.4.

* gnu/packages/libftdi.scm (libftdi)[home-page]: Use HTTPS.

* gnu/packages/textutils.scm (dbacl)[home-page]: Use HTTPS.

* gnu/packages/textutils.scm (dbacl)[arguments]: Substitute INVOKE for SYSTEM* and end phases with #t.

* gnu/packages/patches/glibc-allow-kernel-2.6.32.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/base.scm (glibc/linux)[replacement]: New field.
(glibc-2.26-patched): New variable.

* gnu/packages/web.scm (r-httpuv): Update to 1.3.6.1.

* gnu/packages/statistics.scm (r-lubridate): Update to 1.7.3.

* gnu/packages/statistics.scm (r-tidyselect): Update to 0.2.4.

* gnu/packages/statistics.scm (r-rmarkdown): Update to 1.9.

* gnu/packages/statistics.scm (r-rcpparmadillo): Update to 0.8.400.0.0.

* gnu/packages/statistics.scm (r-yaml): Update to 2.1.17.

* gnu/packages/statistics.scm (r-gdtools): Update to 0.1.7.
[inputs]: Add zlib.

* gnu/packages/statistics.scm (r-rpart): Update to 4.1-13.

* gnu/packages/statistics.scm (r-mass): Update to 7.3-49.

* gnu/packages/databases.scm (r-rmysql): Update to 0.10.14.

* gnu/packages/cran.scm (r-pillar): Update to 1.2.1.

* gnu/packages/cran.scm (r-truncnorm): Update to 1.0-8.

* gnu/packages/bioinformatics.scm (r-scran): Update to 1.6.8.

* gnu/packages/bioinformatics.scm (r-wgcna): Update to 1.63.

* gnu/packages/bioinformatics.scm (r-topgo): Update to 2.30.1.