Submission failure with "make: *** No rule to make target `installsrc'. Stop"

Submission failure with "make: *** No rule to make target `installsrc'. Stop"
https://bugs.webkit.org/show_bug.cgi?id=214696
<rdar://problem/62268104>

Patch by Ryan Hostetler <rhost@apple.com> on 2020-10-04
Reviewed by Darin Adler.

.:

Add installsrc phase to support xbs submitproject for WebKit repository.
This change allows internal tools to submit and build in a single step.

* Makefile:
* Makefile.shared:
* Source/Makefile:

Source/ThirdParty:

Add installsrc phase to support xbs submitproject for WebKit repository.
This change allows internal tools to submit and build in a single step.

* Makefile:

Tools:

Add support for XBS single base project build for WebKit repository.
This change allows internal tools to submit and build from the repository root in a single step.

* Makefile:
Tools does not need to be submitted, so we stub out the installsrc phase.

WebKitLibraries:

Add support for XBS single base project build for WebKit repository.
This change allows internal tools to submit and build from the repository root in a single step.

* Makefile:
WebKitLibraries do not need to be submitted, so we stub out the installsrc phase.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@267949 268f45cc-cd09-0410-ab3c-d52691b4dbfc