gnu: libepoxy: Fix tests on arm.

* gnu/packages/gl.scm (libepoxy)[arguments]: When building for arm,
  patch test/dlwrap.c to fix the tests.

Merge branch 'master' into core-updates

gnu: p11-kit: Update to 0.23.1.

* gnu/packages/gnutls.scm (p11-kit): Update to 0.23.1.

gnu: net-tools: Adapt to linux-libre-headers-3.14.x.

* gnu/packages/linux.scm (net-tools): Remove the HAVE_HWSTRIP and HAVE_HWTR
  options from the configuration.

services: Add upower.

* gnu-system.am (GNU_SYSTEM_MODULES): Add gnu/services/upower.scm.
* gnu/services/upower.scm: New file, defining a upower service.
* doc/guix.texi (Various Services): Mention it.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

gnu: Add upower.

* gnu/packages/gnome.scm (upower): New variable.
* gnu/packages/patches/upower-builddir.patch: New patch.
* gnu-system.am (dist_patch_DATA): Add it.

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

lint: Add a 'derivation' checker.

* guix/scripts/lint.scm (check-derivation): New procedure.
  (%checkers): Add 'derivation' checker.
* tests/lint.scm ("derivation: invalid arguments"): New test.

gnu: gnutls: Update to 3.4.0.

* gnu/packages/patches/gnutls-fix-duplicate-manpages.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gnutls.scm (gnutls)[source]: Update to 3.4.0.  Add patch.
  [arguments]: Pass --without-p11-kit to 'configure'.
  [propagated-inputs]: Use 'nettle' instead of 'nettle-2'.  Add 'libidn'.

gnu: gnutls: Add debug output.

* gnu/packages/gnutls.scm (gnutls)[outputs]: Add debug output.

gnu: nettle: Add debug output.

* gnu/packages/nettle.scm (nettle)[outputs]: Add debug output.

doc: Add example showing how to customize 'nscd-service'.

* doc/guix.texi (Name Service Switch): Add link to nss-mdns.  Add
  example show how to pass #:name-services to 'nscd-service'.
  (Base Services): Add link from 'nscd-service' to the above.
* gnu/services/base.scm (nscd-service): Update docstring accordingly.

gnu: man-pages: Update to 3.82.

* gnu/packages/man.scm (man-pages): Update to 3.82.

system: Allow users to PTRACE_ATTACH to their own processes.

* gnu/build/activation.scm (activate-ptrace-attach): New procedure.
* gnu/system.scm (operating-system-activation-script): Use it.

build: Build and install (guix build-system haskell).

* Makefile.am (MODULES): Add guix/build-system/haskell.scm.

gnu: gtk+: Pass --with-html-dir=$doc.

Fixes a regression introduced in 6b1f238.

* gnu/packages/gtk.scm (gtk+)[arguments]: Add #:configure-flags.

gnu: elfutils: Add $libdir to the RUNPATH of binaries.

* gnu/packages/elf.scm (elfutils)[arguments]: New field.

gnu: elfutils: Work around PTRACE_ATTACH-induced test failures.

* gnu/packages/patches/elfutils-tests-ptrace.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/elf.scm (elfutils)[source]: Use it.

packages: 'package-transitive-supported-systems' accounts for implicit inputs.

Reported by Federico Beffa.

* guix/packages.scm (package-transitive-supported-systems): Use
  bag-direct-inputs + package->bag rather than package-direct-inputs.
* tests/packages.scm ("package-transitive-supported-systems"): Add
  explicit 'build-system' field to each 'dummy-package' form.
  ("package-transitive-supported-systems, implicit inputs"): New test.

packages: Add 'bag-direct-inputs'.

* guix/packages.scm (bag-direct-inputs): New procedure.
  (bag-transitive-inputs): Use it.

gnu: nspr: Add $libdir to the RUNPATH of binaries.

* gnu/packages/gnuzilla.scm (nspr)[arguments]: Add
  LDFLAGS=-Wl,-rpath=$libdir to #:configure-flags.