config: teach "git -c" to recognize an empty string

In a config file, you can do:

  [foo]
  bar

to turn the "foo.bar" boolean flag on, and you can do:

  [foo]
  bar=

to set "foo.bar" to the empty string. However, git's "-c"
parameter treats both:

  git -c foo.bar

and

  git -c foo.bar=

as the boolean flag, and there is no way to set a variable
to the empty string. This patch enables the latter form to
do that.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jk/command-line-config-empty-string' into jch

* jk/command-line-config-empty-string:
  config: teach "git -c" to recognize an empty string

Conflicts:
	config.c
RelNotes: no more check_ref_format micro-optimization

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Release notes: grammatical fixes

Signed-off-by: Marc Branchaud <marcnarc@xiplink.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
SQUASH??? mergetool.prompt
Merge branch 'mb/relnotes-2.1' into jch

* mb/relnotes-2.1:
  SQUASH??? mergetool.prompt
  Release notes: grammatical fixes
  RelNotes: no more check_ref_format micro-optimization
imap-send doc: omit confusing "to use imap-send" modifier

It wouldn't make sense for these configuration variables to be
required for Git in general to function.  'Required' in this context
means required for git imap-send to work.

Noticed while trying to figure out what the sentence describing
imap.tunnel meant.

[jn: expanded to also simplify explanation of imap.folder and
 imap.host in the same way]

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'bc/imap-send-doc' into jch

* bc/imap-send-doc:
  imap-send doc: omit confusing "to use imap-send" modifier
Documentation: git-init: typographical fixes

Signed-off-by: Linus Arver <linusarver@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: git-init: list items facelift

No textual change.

Signed-off-by: Linus Arver <linusarver@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: git-init: template directory: reword

Signed-off-by: Linus Arver <linusarver@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: git-init: --separate-git-dir: clarify

Signed-off-by: Linus Arver <linusarver@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: git-init: reword parenthetical statements

Signed-off-by: Linus Arver <linusarver@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: git-init: template directory: reword and cross-reference

Signed-off-by: Linus Arver <linusarver@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: git-init: flesh out example

Signed-off-by: Linus Arver <linusarver@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'la/init-doc' into jch

* la/init-doc:
  Documentation: git-init: flesh out example
  Documentation: git-init: template directory: reword and cross-reference
  Documentation: git-init: reword parenthetical statements
  Documentation: git-init: --separate-git-dir: clarify
  Documentation: git-init: template directory: reword
  Documentation: git-init: list items facelift
  Documentation: git-init: typographical fixes