ninja: Don't add a new ninja-level variable for libdirs.

$libdirs was always in front of $libs, so there's no need for a second variable.
If $libdirs is empty, the link line no longer contains two spaces, ninja needs
to do fewer variable lookups when parsing .ninja files, and libdirs evaluation
moves to WriteLink() -- there's no need to write libdirs for static libraries
for example.

No intended behavior change.

R=mark@chromium.org

Review URL: https://codereview.chromium.org/18793003

git-svn-id: http://gyp.googlecode.com/svn/trunk@1664 78cadc50-ecff-11dd-a971-7dbc132099af
ninja: Only write ar_host, cc_host, cxx_host, ld_host in multi-toolset builds.

No intended functionality change: They are only used for targets with a toolset
of 'host', which only happens only if generator_supports_multiple_toolsets is
true.

Saves a whopping 4 lines (out of ~148000) in ninja files (but it's within
the first 8 lines of build.ninja, so it's at least somewhat visible 4 lines?)

R=fischman@chromium.org, michaelbai@chromium.org

Review URL: https://codereview.chromium.org/18236003

git-svn-id: http://gyp.googlecode.com/svn/trunk@1665 78cadc50-ecff-11dd-a971-7dbc132099af
Default to parallel gyp on non-win platforms

Setting GYP_PARALLEL=0 on posix will turn off parallel gyp.

BUG=chromium:154205
R=dmazzoni@chromium.org, thakis@chromium.org

Review URL: https://codereview.chromium.org/18603014

git-svn-id: http://gyp.googlecode.com/svn/trunk@1666 78cadc50-ecff-11dd-a971-7dbc132099af
Make root invocation less crazy so that multiprocessing works on Windows

Previously gyp.bat runs "python gyp" and "gyp" imports "gyp" expecting to
get pylib/gyp/__init__.py. Multiprocessing tries to fork and doesn't find
the entry point named gyp because it doesn't search for non-.py
extensions.

Instead, make non-Windows match with a wrapper 'gyp' in bash, and make the
python entry point gyp_main.py so that importing works more normally.

Also, remove "Using parallel processing..." message so that tests pass,
otherwise they complain that there was output on stderr. This was failing
on other OSs too.

R=thakis@chromium.org
BUG=154205

Review URL: https://codereview.chromium.org/18271010

git-svn-id: http://gyp.googlecode.com/svn/trunk@1667 78cadc50-ecff-11dd-a971-7dbc132099af
Fix fake assembler on vs2012

(causing tests to fail currently)

TBR=bradnelson@google.com

Review URL: https://codereview.chromium.org/18500016

git-svn-id: http://gyp.googlecode.com/svn/trunk@1668 78cadc50-ecff-11dd-a971-7dbc132099af
fix interpreter and line endings for 'gyp'

After r1667.

TBR=thakis@chromium.org

Review URL: https://codereview.chromium.org/18778003

git-svn-id: http://gyp.googlecode.com/svn/trunk@1669 78cadc50-ecff-11dd-a971-7dbc132099af
Fix the *nix invocation script after r1667

R=thakis@chromium.org

Review URL: https://codereview.chromium.org/18856011

git-svn-id: http://gyp.googlecode.com/svn/trunk@1670 78cadc50-ecff-11dd-a971-7dbc132099af