gnu: ed: Upgrade to 1.10.

* gnu/packages/ed.scm (ed): Upgrade to 1.10.  Use '.tar.lz' file, and
  add 'native-inputs' field.

gnu: ocrad: Upgrade to 0.23.

* gnu/packages/ocrad.scm (ocrad): Upgrade to 0.23.

gnu: tcl: Install man pages in share/man.

* gnu/packages/tcl.scm (tcl): Add --mandir configure flag.

gnu: gnu-pw-mgr: Fix download location.

* gnu/packages/gnu-pw-mgr.scm (gnu-pw-mgr): Fix download location.

gnu: Add mc

* gnu/packages/mc.scm: New file
* gnu/packages/patches/mc-fix-ncurses-build.patch: New patch
* gnu-system.am (GNU_SYSTEM_MODULES): Add mc.scm.
(dist_patch_DATA): Add patch

gnu: libssh2: Fix use with libssh2.pc

* gnu/packages/ssh.scm (libssh2): Pass --with-libgcrypt configure flag and
  propagate inputs.

Merge branch 'core-updates'

gnu: gp2c: Upgrade to 0.0.8pl1.

* gnu/packages/algebra.scm (gp2c): Upgrade to 0.0.8pl1, add native input perl.

gnu: pari-gp: Upgrade to 2.7.0.

* gnu/packages/algebra.scm (pari-gp): Upgrade to 2.7.0.

gnu: gnu-pw-mgr: Upgrade to 1.2

* gnu/packages/gnu-pw-mgr.scm: Upgrade to 1.2

gnu: guile-ssh: Upgrade to 0.6.0.

* gnu/packages/ssh.scm (guile-ssh): Upgrade to 0.6.0.
  [arguments]: Remove #:tests? #f; add #:parallel-build? #f.

gnu: recutils: Upgrade to 1.7.

* gnu/packages/recutils.scm (recutils): Upgrade to 1.7.
  Add 'arguments' field.

gnu: Add cursynth

* gnu/packages/cursynth.scm: New file
* gnu-system.am (GNU_SYSTEM_MODULES): Add it

gnu: remove python-fix-dbm.patch

* gnu/packages/patches/python-fix-dbm.patch: remove file. It is not needed
  anymore, and is probably a left-over of a failed merge.
* gnu-system.am: remove gnu/packages/patches/python-fix-dbm.patch

gnu: Enable tests in Python 3.

* gnu/packages/python.scm: enable tests for Python 3
* gnu/packages/python-fix-tests.patch: New file.
* gnu/packages/gnu-system.am (dist_patch_DATA): add it.

gnu: Python: use /nix/.../sh instead of /bin/sh in the subprocess module

* gnu/packages/python.scm (python-2): patch Lib/subprocess.py to use
  /nix/.../sh.

gnu: Enable the 'ctypes' module in Python.

* gnu/packages/python.scm (python-2): add libffi to the inputs and use it to
  build the ctypes module.

gnu: autotools: Add Autoconf 2.68; turn 'autoconf-wrapper' into a procedure.

* gnu/packages/autotools.scm (autoconf-2.68): New variable.
  (autoconf-wrapper): Turn into a procedure.  Turn comment into a
  docstring.
  (automake): Adjust accordingly.

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

gnu: glibc: Patch mtrace.pl to avoid retaining a reference to Perl.

* gnu/packages/base.scm (glibc)[argument] <pre-configure phase>: Patch
  malloc/mtrace.pl.

gnu: tor: Upgrade to 0.2.4.21.

* gnu/packages/tor.scm (tor): Upgrade to 0.2.4.21.