Add build*/ to .gitignore to support the typical commandline cmake
workflow for out-of-source builds. That is, something like:

mkdir build-x64-static
cd build-x64-static
cmake ../contrib/buildsystems -DCMAKE_BUILD_TYPE=Release `
	-DVCPKG_ARCH=x64-windows-static `
	-G Ninja
ninja

Signed-off-by: Rafael Kitover <[email protected]>

Change the usage message that is printed when the arch is not passed in
in vcpkg_install.bat to mention the -static vcpkg triplets for static
builds.

Signed-off-by: Rafael Kitover <[email protected]>

Use IF EXIST path/vcpkg.exe instead of dir path/vcpkg.exe && to check
for an existing vcpkg.exe which is the typical way to do these tests in
cmd scripts.

Signed-off-by: Rafael Kitover <[email protected]>

Indent and format the code in the IF statement checking for the
non-existence of git.exe.

Signed-off-by: Rafael Kitover <[email protected]>

Append >&2 to the echo statements for the missing arch message and the
git not found messages to send them to stderr instead of stdout which is
the typical practice.

Signed-off-by: Rafael Kitover <[email protected]>

If %VCPKG_ROOT% environment variable is set, check that the parent
directory exists and throw an error if it does not.

If %VCPKG_ROOT% is not set, set it to %cwd%\vcpkg, which was the
previous behavior.

Change all references to %cwd%\vcpkg to %VCPKG_ROOT%.

Change the documentation in the top comment to refer to %VCPKG_ROOT%.

This allows a developer to maintain his or her own vcpkg clone and not
have to unnecessarily repeat the very time-consuming process of
compiling the dependencies.

Set ENV{VCPKG_ROOT} to the VCPKG_DIR default in CMakeLists.txt, because
the cmake code does not support this yet, this is introduced in a
subsequent commit.

Signed-off-by: Rafael Kitover <[email protected]>

USE_VCPKG is the current variable used to disable vcpkg.

Signed-off-by: Rafael Kitover <[email protected]>

Signed-off-by: Rafael Kitover <[email protected]>

Add WORKING_DIRECTORY to the add_custom_command() call that launches
CreateLinks.cmake, which is a script that creates some hard links to
built git executables. This allows the script to not fail for build
directories other than the default.

Signed-off-by: Rafael Kitover <[email protected]>

Stop displaying the variables MSVC, CMAKE_CXX_COMPILER_ID,
CMAKE_GENERATOR_PLATFORM in the vcpkg setup section, as this section
runs before project() and they are not yet initialized.

Instead display them after the project() call, and use
CMAKE_C_COMPILER_ID instead of CMAKE_CXX_COMPILER_ID as this is a C
project.

Also change all variable log message() calls to message(STATUS ...)
calls.

Signed-off-by: Rafael Kitover <[email protected]>

Use VCPKG_DIR instead of relative path to the default vcpkg clone for
appending the vcpkg bin to PATH when writing GIT-BUILD-OPTIONS in cmake.

Signed-off-by: Rafael Kitover <[email protected]>

Use DEFINED instead of EXISTS (EXISTS is for checking if a filesystem
path exists, DEFINED is for variables.)

Also move the check to above the call to vcpkg_install.bat where it is
used from its previous location below.

Signed-off-by: Rafael Kitover <[email protected]>

Instead of checking if VCPKG_DIR exists first, always call
vcpkg_install.bat, which will create a new vcpkg clone as well as
perform any necessary actions on an existing clone, and will do nothing
if nothing needs to be done.

Remove the "Initializing vcpkg..." message from cmake and change the
"installing libraries" message from the cmd script to say that it may
take a while.

Signed-off-by: Rafael Kitover <[email protected]>

Add the build_option() function which is similar to the cmake option()
command, but allows adding alias variables and alias environment
variables.

The option and all aliases are set to the first found value by listed
sequence in the option and all aliases, followed by the default if
provided, or 'OFF' if not provided, with cache variables having
precedence over normal variables.

In the case of environment variables or aliases, if the type is BOOL and
the found/default value is OFF/FALSE unset the environment variable.

Signed-off-by: Rafael Kitover <[email protected]>

Include the build_option() function introduced in b0d325d4bd (Add
build_option() to cmake/Utilities.cmake., 2022-02-10).

Initialize VCPKG_ARCH with an alias to VCPKG_TARGET_TRIPLET with
build_option().

Add a note about this to the cmake doc.

Signed-off-by: Rafael Kitover <[email protected]>

Use the build_option() function introduced in 3db0658 (build: add
build_option() to cmake/Utilities.cmake, 2022-02-10) to alias the
VCPKG_ROOT environment variable to VCPKG_DIR.

Support for VCPKG_ROOT was added to vcpkg_install.bat in 98c6a0d
(build: support VCPKG_ROOT env in vcpkg_install.bat, 2022-02-08).

Add a note about VCPKG_DIR and ENV{VCPKG_ROOT} to the cmake doc.

Signed-off-by: Rafael Kitover <[email protected]>

Check if NO_<dep> environment variable is defined to skip vcpkg deps,
this is needed to implement cmake support for NO_GETTEXT properly in a
subsequent commit.

Signed-off-by: Rafael Kitover <[email protected]>

Add gettext vcpkg dependency lib with the [tools] feature for the msgfmt
utility to build the translations.

Can be disabled by setting the NO_GETTEXT environment variable, support
for which was added in 2cd6269 (build: support NO_LIB env to disable
vcpkg deps, 2022-03-17).

Signed-off-by: Rafael Kitover <[email protected]>

Make NO_GETTEXT a build option aliased to ENV{NO_GETTEXT} to pass to
vcpkg_install.bat to skip building gettext.

Turn it off by default when vcpkg is in-use because it's a very long
compile.

Do not build translations if NO_GETTEXT is set.

Add a note about NO_GETTEXT to the docs at the top of CMakeLists.txt.

Signed-off-by: Rafael Kitover <[email protected]>