build: Ship the Go implementation by default, not the POSIX shell one

The Go implementation is now considered stable enough for wider use,
and should have feature parity with its POSIX shell counterpart.

https://github.com/containers/toolbox/pull/437

meson.build

@@ -5,7 +5,7 @@ project(
   meson_version: '>= 0.40.0',
 )
 
-go = find_program('go', required: false)
+go = find_program('go')
 go_md2man = find_program('go-md2man')
 shellcheck = find_program('shellcheck', required: false)
 
@@ -20,11 +20,6 @@ if shellcheck.found()
   test('shellcheck', shellcheck, args: [toolbox])
 endif
 
-install_data(
-  toolbox,
-  install_dir: get_option('bindir'),
-)
-
 bash_completion = dependency('bash-completion', required: false)
 if bash_completion.found()
   install_data(

src/meson.build

@@ -19,15 +19,15 @@ sources = files(
   'pkg/version/version.go',
 )
 
-if go.found()
 custom_target(
-    'toolbox-go',
+  'toolbox',
   build_by_default: true,
   command: [go_build_wrapper_program, meson.current_source_dir(), meson.current_build_dir()],
   input: sources,
+  install: true,
+  install_dir: get_option('bindir'),
   output: 'toolbox',
 )
-endif
 
 if shellcheck.found()
   test('shellcheck go-build-wrapper', shellcheck, args: [go_build_wrapper_file])