Fix exe wrapper detection for run targets.

mesonbuild/backend/backends.py

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index e19afca..df9c9eb 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -397,9 +397,17 @@
         if isinstance(exe, dependencies.ExternalProgram):
             exe_cmd = exe.get_command()
             exe_for_machine = exe.for_machine
-        elif isinstance(exe, (build.BuildTarget, build.CustomTarget)):
+        elif isinstance(exe, build.BuildTarget):
             exe_cmd = [self.get_target_filename_abs(exe)]
             exe_for_machine = exe.for_machine
+        elif isinstance(exe, build.CustomTarget):
+            # The output of a custom target can either be directly runnable
+            # or not, that is, a script, a native binary or a cross compiled
+            # binary when exe wrapper is available and when it is not.
+            # This implementation is not exhaustive but it works in the
+            # common cases.
+            exe_cmd = [self.get_target_filename_abs(exe)]
+            exe_for_machine = MachineChoice.BUILD
         else:
             exe_cmd = [exe]
             exe_for_machine = MachineChoice.BUILD
@@ -470,6 +478,8 @@
         if isinstance(exe, (dependencies.ExternalProgram,
                             build.BuildTarget, build.CustomTarget)):
             basename = exe.name
+        elif isinstance(exe, mesonlib.File):
+            basename = os.path.basename(exe.fname)
         else:
             basename = os.path.basename(exe)
 

mesonbuild/backend/ninjabackend.py

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index b93ac39..96ba4fa 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -995,7 +995,7 @@
             target_env = self.get_run_target_env(target)
             _, _, cmd = self.eval_custom_target_command(target)
             desc = 'Running external command {}{}'
-            meson_exe_cmd, reason = self.as_meson_exe_cmdline(target_name, cmd[0], cmd[1:],
+            meson_exe_cmd, reason = self.as_meson_exe_cmdline(target_name, target.command[0], cmd[1:],
                                                               force_serialize=True, env=target_env,
                                                               verbose=True)
             cmd_type = ' (wrapped by meson {})'.format(reason)

mesonbuild/backend/vs2010backend.py

diff --git a/mesonbuild/backend/vs2010backend.py b/mesonbuild/backend/vs2010backend.py
index e94ab49..7bbd2b6 100644
--- a/mesonbuild/backend/vs2010backend.py
+++ b/mesonbuild/backend/vs2010backend.py
@@ -536,7 +536,7 @@
             _, _, cmd_raw = self.eval_custom_target_command(target)
         depend_files = self.get_custom_target_depend_files(target)
         target_env = self.get_run_target_env(target)
-        wrapper_cmd, _ = self.as_meson_exe_cmdline(target.name, cmd_raw[0], cmd_raw[1:],
+        wrapper_cmd, _ = self.as_meson_exe_cmdline(target.name, target.command[0], cmd_raw[1:],
                                                    force_serialize=True, env=target_env,
                                                    verbose=True)
         self.add_custom_build(root, 'run_target', ' '.join(self.quote_arguments(wrapper_cmd)),

run_unittests.py

diff --git a/run_unittests.py b/run_unittests.py
index 23bdff4..e53f0c7 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -7881,7 +7881,6 @@
         # Force tracebacks so we can detect them properly
         env = {'MESON_FORCE_BACKTRACE': '1'}
         error_message = "An exe_wrapper is needed but was not found. Please define one in cross file and check the command and/or add it to PATH."
-        error_message2 = "The exe_wrapper 'broken' defined in the cross file is needed by run target 'run-prog', but was not found. Please check the command and/or add it to PATH."
 
         with self.assertRaises(MesonException) as cm:
             # Must run in-process or we'll get a generic CalledProcessError
@@ -7895,7 +7894,7 @@
             self.init(testdir, extra_args='-Dcustom-target=false',
                       inprocess=True,
                       override_envvars=env)
-        self.assertEqual(str(cm.exception), error_message2)
+        self.assertEqual(str(cm.exception), error_message)
 
         self.init(testdir, extra_args=['-Dcustom-target=false', '-Drun-target=false'],
                   override_envvars=env)

test cases/common/52 run target/meson.build

diff --git a/test cases/common/52 run target/meson.build b/test cases/common/52 run target/meson.build
index a28d218..49e8d75 100644
--- a/test cases/common/52 run target/meson.build
+++ b/test cases/common/52 run target/meson.build
@@ -4,8 +4,11 @@
 # In cross builds exe_wrapper should be added if it exists.
 
 exe = executable('helloprinter', 'helloprinter.c')
-run_target('runhello',
-  command : [exe, 'argument'])
+
+if not meson.is_cross_build() or meson.can_run_host_binaries()
+  run_target('runhello',
+    command : [exe, 'argument'])
+endif
 
 converter = find_program('converter.py')
 
@@ -62,10 +65,12 @@
   configuration: configuration_data()
 )
 
+
 run_target('configure_script',
   command : conf
 )
 
+
 # Target names that clash with potential builtin functionality.
 run_target('ctags',
   command : converter)