devenv: Add executables locations to both PATH and WINEPATH

Handles the case when wine-binfmt is installed, which makes .exe files
executable without without specifying an exe wrapper.

mesonbuild/backend/backends.py

@@ -1850,9 +1850,9 @@ class Backend:
         env = build.EnvironmentVariables()
         extra_paths = set()
         library_paths = set()
+        build_machine = self.environment.machines[MachineChoice.BUILD]
         host_machine = self.environment.machines[MachineChoice.HOST]
-        need_exe_wrapper = self.environment.need_exe_wrapper()
-        need_wine = need_exe_wrapper and host_machine.is_windows()
+        need_wine = not build_machine.is_windows() and host_machine.is_windows()
         for t in self.build.get_targets().values():
             cross_built = not self.environment.machines.matches_build_machine(t.for_machine)
             can_run = not cross_built or not need_exe_wrapper or need_wine
@@ -1874,18 +1874,23 @@ class Backend:
                 # LD_LIBRARY_PATH. This allows running system applications using
                 # that library.
                 library_paths.add(tdir)
+        if need_wine:
+            # Executable paths should be in both PATH and WINEPATH.
+            # - Having them in PATH makes bash completion find it,
+            #   and make running "foo.exe" find it when wine-binfmt is installed.
+            # - Having them in WINEPATH makes "wine foo.exe" find it.
+            library_paths.update(extra_paths)
         if library_paths:
-            if host_machine.is_windows() or host_machine.is_cygwin():
+            if need_wine:
+                env.prepend('WINEPATH', list(library_paths), separator=';')
+            elif host_machine.is_windows() or host_machine.is_cygwin():
                 extra_paths.update(library_paths)
             elif host_machine.is_darwin():
                 env.prepend('DYLD_LIBRARY_PATH', list(library_paths))
             else:
                 env.prepend('LD_LIBRARY_PATH', list(library_paths))
         if extra_paths:
-            if need_wine:
-                env.prepend('WINEPATH', list(extra_paths), separator=';')
-            else:
-                env.prepend('PATH', list(extra_paths))
+            env.prepend('PATH', list(extra_paths))
         return env
 
     def compiler_to_generator(self, target: build.BuildTarget,