mesonlib: handle meson exe wrappers

There are cases when it is useful to wrap the main meson executable with
a script that sets up environment variables, passes --cross-file, etc.
For example, in a Yocto SDK, we need to point to the right meson.cross
so that everything "just works", and we need to alter CC, CXX, etc. In
such cases, it can happen that the "meson" found in the path is actually
a wrapper script that invokes the real meson, which may be in another
location (e.g. "meson.real" or similar).

Currently, in such a situation, meson gets confused because it tries to
invoke itself using the "meson" executable (which points to the wrapper
script) instead of the actual meson (which may be called "meson.real" or
similar). In fact, the wrapper script is not necessarily even Python, so
the whole thing fails.

Fix this by using Python imports to directly find mesonmain.py instead
of trying to detect it heuristically. In addition to fixing the wrapper
issue, this should make the detection logic much more robust.

1 files changed, 2 insertions, 0 deletions

diff --git a/run_cross_test.py b/run_cross_test.py
index 7191402..22e1972 100755
--- a/run_cross_test.py
+++ b/run_cross_test.py
@@ -28,6 +28,7 @@ from pathlib import Path
 
 from run_project_tests import gather_tests, run_tests, StopException, setup_commands
 from run_project_tests import failing_logs
+from run_tests import setup_pythonpath
 
 def runtests(cross_file):
     commontests = [('common', gather_tests(Path('test cases', 'common')), False)]
@@ -46,5 +47,6 @@ def runtests(cross_file):
 
 if __name__ == '__main__':
     setup_commands('ninja')
+    setup_pythonpath()
     cross_file = sys.argv[1]
     runtests(cross_file)