MSVC: link in invalidcontinue.obj for better POSIX compatibility

By default, Windows abort()'s instead of setting
errno=EINVAL when invalid arguments are passed to standard functions.

For example, when PAGER quits and git detects it with
errno=EPIPE on write(), check_pipe() in write_or_die.c tries raise(SIGPIPE)
but since there is no SIGPIPE on Windows, it is treated as invalid argument,
causing abort() and crash report window.

Linking in invalidcontinue.obj (provided along with MS compiler) allows
raise(SIGPIPE) to return with errno=EINVAL.

Signed-off-by: Marat Radchenko <marat@slonopotamus.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
MSVC: fix t0040-parse-options crash

On 64-bit MSVC, pointers are 64 bit but `long` is only 32.
Thus, casting string to `unsigned long`, which is redundand on other
platforms, throws away important bits and when later cast to `intptr_t`
results in corrupt pointer.

This patch fixes test-parse-options by replacing harming cast with
correct one.

Signed-off-by: Marat Radchenko <marat@slonopotamus.org>
MSVC: allow linking with the cURL library

Teach the clink.pl script that -lcurl is a request to link with the
cURL library, and drop NO_CURL from config.mak.uname for the MSVC
platform.

Signed-off-by: Marat Radchenko <marat@slonopotamus.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
MSVC: allow using ExtUtils::MakeMaker

Drop NO_PERL_MAKEMAKER from config.mak.uname for the MSVC platform.

MakeMaker is available on Windows Perl implementations and
installs modules to correct location, unlike NO_PERL_MAKEMAKER Makefile.

Signed-off-by: Marat Radchenko <marat@slonopotamus.org>