Changed code to use detected executables rather than hardcoding sys.executable.

mesonbuild/mesonlib.py

@@ -22,6 +22,15 @@ import collections
 
 from glob import glob
 
+if sys.executable.endswith('meson.exe'):
+    # In Windows and using the MSI installed executable.
+    meson_command = [sys.executable]
+    python_command = [sys.executable, 'runpython']
+else:
+    meson_command = [sys.executable, os.path.join(os.path.split(__file__)[0], '..', 'meson.py')]
+    python_command = [sys.executable]
+
+
 # Put this in objects that should not get dumped to pickle files
 # by accident.
 import threading

mesonbuild/modules/python3.py

@@ -52,7 +52,7 @@ class Python3Module(ExtensionModule):
 
     @noKwargs
     def find_python(self, state, args, kwargs):
-        py3 = dependencies.ExternalProgram('python3', sys.executable, silent=True)
+        py3 = dependencies.ExternalProgram('python3', mesonlib.python_command, silent=True)
         return ModuleReturnValue(py3, [py3])
 
     @noKwargs