Make --host work for ./build-userland, ./build-dhrystone, etc. in addition to just ./build-modules

common.py

@@ -499,6 +499,17 @@ options are given, for example --static, since users don't usually want
 static executables to be placed in the final image, but rather only for
 user mode simulations in simulators that don't support dynamic linking like gem5.
 '''
+        )
+        self.add_argument(
+            '--host',
+            default=False,
+            help='''\
+Use the host toolchain and other dependencies to build exectuables for host execution.
+Automatically place the build output on a separate directory from non --host builds,
+e.g. by defaulting --userland-build-id host if that option has effect for the package.
+Make --copy-overlay default to False as the generated executables can't in general
+be run in the guest.
+''',
         )
         self.add_argument(
             '--out-rootfs-overlay-dir-prefix',
@@ -694,6 +705,8 @@ Incompatible archs are skipped.
         if not env['_args_given']['userland_build_id']:
             if env['static']:
                 env['userland_build_id'] = 'static'
+            elif env['host']:
+                env['userland_build_id'] = 'host'
             else:
                 env['userland_build_id'] = env['default_build_id']
         if not env['_args_given']['gem5_build_id']:
@@ -954,7 +967,7 @@ Incompatible archs are skipped.
             env['userland_build_dir'] = join(env['out_dir'], 'userland', env['userland_build_id'], env['arch'])
         env['package'] = set(env['package'])
         if not env['_args_given']['copy_overlay']:
-            if self.env['in_tree'] or self.env['static']:
+            if self.env['in_tree'] or self.env['static'] or self.env['host']:
                 env['copy_overlay'] = False
 
         # Kernel modules.
@@ -1082,6 +1095,8 @@ lunch aosp_{}-eng
         if not env['_args_given']['gcc_which']:
             if env['mode'] == 'baremetal':
                 env['gcc_which'] = 'crosstool-ng'
+            elif env['host']:
+                env['gcc_which'] = 'host'
         if env['gcc_which'] == 'buildroot':
             env['toolchain_prefix'] = os.path.join(
                 env['buildroot_host_bin_dir'],