Set version in project file

Let's set the version in the meson file instead of declaring it outside.

In case git is installed we use the git hash as version. Instead it
isn't (like on a clean build system), let's use the version defined in
the project.

meson.build

@@ -1,6 +1,7 @@
 project(
 	'sway',
 	'c',
+	version: '1.0',
 	license: 'MIT',
 	meson_version: '>=0.48.0',
 	default_options: [
@@ -127,17 +128,12 @@ endif
 
 add_project_arguments('-DSYSCONFDIR="/@0@"'.format(join_paths(prefix, sysconfdir)), language : 'c')
 
-version = get_option('sway-version')
-if version != ''
-	version = '"@0@"'.format(version)
-else
-	if not git.found()
-		error('git is required to make the version string')
-	endif
-
+if git.found()
 	git_commit_hash = run_command([git.path(), 'describe', '--always', '--tags']).stdout().strip()
 	git_branch = run_command([git.path(), 'rev-parse', '--abbrev-ref', 'HEAD']).stdout().strip()
 	version = '"@0@ (" __DATE__ ", branch \'@1@\')"'.format(git_commit_hash, git_branch)
+else
+	version = '"@0@"'.format(meson.project_version())
 endif
 add_project_arguments('-DSWAY_VERSION=@0@'.format(version), language: 'c')
 

meson_options.txt

@@ -1,4 +1,3 @@
-option('sway-version', type : 'string', description: 'The version string reported in `sway --version`.')
 option('default-wallpaper', type: 'boolean', value: true, description: 'Install the default wallpaper.')
 option('zsh-completions', type: 'boolean', value: true, description: 'Install zsh shell completions.')
 option('bash-completions', type: 'boolean', value: true, description: 'Install bash shell completions.')