[PATCH v4 0/9] post-v2.33 "drop support for ancient curl" follow-up

This is a follow-up to the already-integrated topic for dropping support for older curl versions submitted before the v2.33 release[1].

See https://lore.kernel.org/git/cover-v3-0.9-00000000000-20210911T092751Z-avarab@gmail.com [1] for v3.

This is a hopefully final re-roll with a small grammar improvement in 3/8. See range-diff, pointed out/requested at https://lore.kernel.org/git/YTzBUFY4p6obEqF+@coredump.intra.peff.net/

Ævar Arnfjörð Bjarmason (9):
  INSTALL: don't mention the "curl" executable at all
  INSTALL: reword and copy-edit the "libcurl" section
  INSTALL: mention that we need libcurl 7.19.4 or newer to build
  Makefile: drop support for curl < 7.9.8 (again)
  http: drop support for curl < 7.18.0 (again)
  http: correct version check for CURL_HTTP_VERSION_2
  http: correct curl version check for CURLOPT_PINNEDPUBLICKEY
  http: centralize the accounting of libcurl dependencies
  http: don't hardcode the value of CURL_SOCKOPT_OK

 INSTALL           |  15 +++---
 Makefile          |  11 +---
 git-curl-compat.h | 128 ++++++++++++++++++++++++++++++++++++++++++++++
 http.c            |  35 ++++++-------
 imap-send.c       |   2 +-
 5 files changed, 157 insertions(+), 34 deletions(-)
 create mode 100644 git-curl-compat.h

Range-diff against v3:
 -:  ----------- >  1:  7b771aa70ef INSTALL: don't mention the "curl" executable at all
 1:  3b0119958a3 =  2:  2f3a09c98d2 INSTALL: reword and copy-edit the "libcurl" section
 2:  dce6520a5c9 !  3:  59c86f14cef INSTALL: mention that we need libcurl 7.19.4 or newer to build
    @@ INSTALL: Issues of note:
      	  not need that functionality, use NO_CURL to build without
      	  it.
      
    -+	  Git requires version "7.19.4" or later of "libcurl", to
    -+	  build (without NO_CURL). This version requirement may be
    -+	  bumped in the future.
    ++	  Git requires version "7.19.4" or later of "libcurl" to build
    ++	  without NO_CURL. This version requirement may be bumped in
    ++	  the future.
     +
      	- "expat" library; git-http-push uses it for remote lock
      	  management over DAV.  Similar to "curl" above, this is optional
 3:  98cdb7c35a9 =  4:  6edd01ad125 Makefile: drop support for curl < 7.9.8 (again)
 4:  7919debfd89 =  5:  73ad0d4cb28 http: drop support for curl < 7.18.0 (again)
 5:  67bc1992762 =  6:  f4d1de8a112 http: correct version check for CURL_HTTP_VERSION_2
 6:  db7d6029dda =  7:  7aa5149c395 http: correct curl version check for CURLOPT_PINNEDPUBLICKEY
 7:  e2e53cbfba1 =  8:  9890e4b662a http: centralize the accounting of libcurl dependencies
 8:  4bdec34a545 =  9:  846b466fdd5 http: don't hardcode the value of CURL_SOCKOPT_OK