gnu: Add vim-nerdcommenter.

* gnu/packages/vim.scm (vim-nerdcommenter): New variable.

Signed-off-by: Efraim Flashner <efraim@flashner.co.il>

gnu: emacs-flymake-shellcheck: Add reference to shellcheck.

* gnu/packages/emacs-xyz.scm (emacs-flymake-shellcheck)
[inputs]: Add shellcheck.
[arguments]: Add substitute-shellcheck-path phase.

Signed-off-by: Efraim Flashner <efraim@flashner.co.il>

Revert "gnu: webkitgtk: Use GCC 11 instead of Clang."

This reverts commit 63f78f6a6ea0d33f3b1fa68c7285cfb865677211.
It led to broken builds of epiphany, gnome-online-accounts, yelp,
zenity, surf, and possibly others.

gnu: emacs-eshell-did-you-mean: Update to 0.2.

* gnu/packages/emacs-xyz.scm (emacs-eshell-did-you-mean): Update to 0.2.

gnu: emacs-ebib: Update to 2.33.

* gnu/packages/emacs-xyz.scm (emacs-ebib): Update to 2.33.

gnu: webkitgtk: Use GCC 11 instead of Clang.

WebkitGTK still compiles fine on x86_64 using GCC 11.  This is the only
architecture known to compile currently, as i686 fails with Clang and others
fail due to unsatisfied dependencies.

* gnu/packages/webkit.scm (webkitgtk)[#:phases]: Drop
‘prepare-build-environment’.
[native-inputs]: Drop clang, add gcc.

gnu: linux-libre 4.4: Update to 4.4.291.

* gnu/packages/linux.scm (linux-libre-4.4-version): Update to 4.4.291.
(linux-libre-4.4-pristine-source): Update hash.

gnu: linux-libre 4.9: Update to 4.9.289.

* gnu/packages/linux.scm (linux-libre-4.9-version): Update to 4.9.289.
(linux-libre-4.9-pristine-source): Update hash.

gnu: linux-libre 4.14: Update to 4.14.254.

* gnu/packages/linux.scm (linux-libre-4.14-version): Update to 4.14.254.
(linux-libre-4.14-pristine-source): Update hash.

gnu: linux-libre 4.19: Update to 4.19.215.

* gnu/packages/linux.scm (linux-libre-4.19-version): Update to 4.19.215.
(linux-libre-4.19-pristine-source): Update hash.

gnu: linux-libre 5.4: Update to 5.4.157.

* gnu/packages/linux.scm (linux-libre-5.4-version): Update to 5.4.157.
(linux-libre-5.4-pristine-source): Update hash.

gnu: linux-libre 5.10: Update to 5.10.77.

* gnu/packages/linux.scm (linux-libre-5.10-version): Update to 5.10.77.
(linux-libre-5.10-pristine-source): Update hash.

gnu: linux-libre: Update to 5.14.16.

* gnu/packages/linux.scm (linux-libre-5.14-version): Update to 5.14.16.
(linux-libre-5.14-pristine-source): Update hash.

gnu: flightgear: Prepare to run test suite.

* gnu/packages/games.scm (flightgear)[arguments]: Add phase to build
test binary. Add phase to skip some failing tests. Move 'check phase to
after 'install-data.

gnu: flightgear: Use system cppunit.

* gnu/packages/games.scm (flightgear)[source]: Adjust snippet to remove
bundled cppunit.
[arguments]: Add configure-flag to use system cppunit.

gnu: simgear: Remove bundled expat.

* gnu/packages/games.scm (simgear)[source]: Add snippet to remove
bundled expat.
[arguments]: Add configure-flag to use system expat.

gnu: Remove openscenegraph-3.4.

* gnu/packages/graphics.scm (openscenegraph-3.4): Remove variable.

gnu: flightgear: Build with newer inputs.

* gnu/packages/games.scm (flightgear)[inputs]: Replace
openscenegraph-3.4 with openscenegraph, boost-for-mysql with boost.
(simgear)[inputs]: Same.

gnu: simgear: Honor #:tests? flag.

* gnu/packages/games.scm (simgear)[arguments]: Adjust custom 'check
phase to honor the #:tests? flag.

gnu: flightgear: Build with qt-build-system.

* gnu/packages/games.scm (flightgear)[build-system]: Switch to
qt-build-system.
[arguments]: Remove 'wrap-executable phase.