src: Support passing of Go build options

Some downstreams (e.g., Fedora) set additional flags while building
software in their repositories. This also applies to software written in
Go. This work removes the need for manually patching the 'go build'
wrapper script, needed for integrating 'go build' into Meson, to add the
desired build options.

This introduces a new build option 'build_flags'.

meson_options.txt

@@ -24,3 +24,9 @@ option(
   type: 'boolean',
   value: true,
 )
+
+option(
+  'build_flags',
+  description: 'Options passed to \'go build\' during build',
+  type: 'string',
+)

src/go-build-wrapper.py

@@ -17,19 +17,21 @@
 #
 
 import os
+import shlex
 import subprocess
 import sys
 
 prog_name = os.path.basename(sys.argv[0])
 
-if len(sys.argv) != 7:
+if len(sys.argv) != 8:
     print('{}: wrong arguments'.format(prog_name), file=sys.stderr)
     print('''Usage: {} [SOURCE DIR]
                            [OUTPUT DIR]
                            [VERSION]
                            [C COMPILER]
                            [DYNAMIC LINKER]
-                           [MIGRATION PATH FORCOREOS/TOOLBOX]'''.format(prog_name), file=sys.stderr)
+                           [MIGRATION PATH FORCOREOS/TOOLBOX]
+                           [BUILD FLAGS]'''.format(prog_name), file=sys.stderr)
     sys.exit(1)
 
 source_dir = sys.argv[1]
@@ -38,6 +40,7 @@
 cc = sys.argv[4]
 dyn_linker = sys.argv[5]
 coreos_migration = sys.argv[6]
+build_flags = sys.argv[7]
 
 os.chdir(source_dir)
 
@@ -84,6 +87,9 @@
 if coreos_migration:
     build_cmd.extend(['-tags', 'migration_path_for_coreos_toolbox'])
 
+if build_flags:
+    build_cmd.extend(shlex.split(build_flags))
+
 build_cmd.extend([
     '-ldflags',
     f'-extldflags \'-Wl,-dynamic-linker,{dynamic_linker} -Wl,-rpath,{rpath}\' -linkmode external -X github.com/containers/toolbox/pkg/version.currentVersion={version}'

src/meson.build

@@ -57,6 +57,7 @@ custom_target(
     cc.cmd_array().get(-1),
     dynamic_linker,
     migration_path_for_coreos_toolbox.to_string(),
+    get_option('build_flags'),
   ],
   input: sources,
   install: true,