project: Add HOMEPAGE_URL named parameter

This sets variables like PROJECT_HOMEPAGE_URL, which can be
used as default values for various things (packaging modules,
doxygen defaults, etc.). Some packaging modules have been
updated to do this as part of this commit.

Co-Author: Craig Scott <craig.scott@crascit.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/Help/variable/CMAKE_PROJECT_HOMEPAGE_URL.rst b/Help/variable/CMAKE_PROJECT_HOMEPAGE_URL.rst
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+++ b/Help/variable/CMAKE_PROJECT_HOMEPAGE_URL.rst
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+CMAKE_PROJECT_HOMEPAGE_URL
+--------------------------
+
+The homepage URL of the top level project.
+
+This variable holds the homepage URL of the project as specified in the top
+level CMakeLists.txt file by a :command:`project` command.  In the event that
+the top level CMakeLists.txt contains multiple :command:`project` calls,
+the most recently called one from that top level CMakeLists.txt will determine
+the value that ``CMAKE_PROJECT_HOMEPAGE_URL`` contains.  For example, consider
+the following top level CMakeLists.txt:
+
+.. code-block:: cmake
+
+  cmake_minimum_required(VERSION 3.0)
+  project(First HOMEPAGE_URL "http://first.example.com")
+  project(Second HOMEPAGE_URL "http://second.example.com")
+  add_subdirectory(sub)
+  project(Third HOMEPAGE_URL "http://third.example.com")
+
+And ``sub/CMakeLists.txt`` with the following contents:
+
+.. code-block:: cmake
+
+  project(SubProj HOMEPAGE_URL "http://subproj.example.com")
+  message("CMAKE_PROJECT_HOMEPAGE_URL = ${CMAKE_PROJECT_HOMEPAGE_URL}")
+
+The most recently seen :command:`project` command from the top level
+CMakeLists.txt would be ``project(Second ...)``, so this will print::
+
+  CMAKE_PROJECT_HOMEPAGE_URL = http://second.example.com
+
+To obtain the homepage URL from the most recent call to :command:`project` in
+the current directory scope or above, see the :variable:`PROJECT_HOMEPAGE_URL`
+variable.