Build clean-up.

* jk/make-fix-dependencies:
  Makefile: silence perl/PM.stamp recipe
  Makefile: avoid timestamp updates to GIT-BUILD-OPTIONS
  Makefile: drop dependency between git-instaweb and gitweb

Test clean-up.

* jk/skip-http-tests-under-no-curl:
  tests: skip dav http-push tests under NO_EXPAT=NoThanks
  t/lib-httpd.sh: skip tests if NO_CURL is defined

Every time we run "make", we update perl/PM.stamp, which
contains a list of all of the perl module files (if it's
updated, we need to rebuild perl/perl.mak, since the
Makefile will not otherwise know about the new files).

This means that every time "make" is run, we see:

      GEN perl/PM.stamp

in the output, even though it is not likely to have changed.
Let's make this recipe completely silent, as we do for other
auto-generated dependency files (e.g., GIT-CFLAGS).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

We force the GIT-BUILD-OPTIONS recipe to run every time
"make" is invoked. We must do this to catch new options
which may have come from the command-line or environment.

However, we actually update the file's timestamp each time
the recipe is run, whether anything changed or not. As a
result, any files which depend on it (for example, all of
the perl scripts, which need to know whether NO_PERL was
set) will be re-built every time.

Let's do our usual trick of writing to a tempfile, then
doing a "cmp || mv" to update the file only when something
changed.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The rule for "git-instaweb" depends on "gitweb". This makes
no sense, because:

  1. git-instaweb has no build-time dependency on gitweb; it
     is a run-time dependency

  2. gitweb is a directory that we want to recursively make
     in. As a result, its recipe is marked .PHONY, which
     causes "make" to rebuild git-instaweb every time it is
     run.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

When built with NO_EXPAT=NoThanks, we will not have a working http-push
over webdav.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

We now detect number of CPUs on older BSD-derived systems.

* km/bsd-sysctl:
  thread-utils.c: detect CPU count on older BSD-like systems
  configure: support HAVE_BSD_SYSCTL option

On BSD-compatible systems some information such as the number
of available CPUs may only be available via the sysctl function.

Add support for a HAVE_BSD_SYSCTL option complete with autoconf
support and include the sys/syctl.h header when the option is
enabled to make the sysctl function available.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Certain older vintages of cURL give irregular output from
"curl-config --vernum", which confused our build system.

* tc/curl-vernum-output-broken-in-7.11:
  Makefile: handle broken curl version number in version check

* km/gettext-n:
  gettext.h: add parentheses around N_ expansion if supported