Fix two errors when cross-compiling with Vala

- AttributeError: 'ValaCompiler' object has no attribute 'get_program_dirs'

  Fixed by adding a `get_program_dirs()` function to the base Compiler
  class, to match `get_library_dirs()`

- KeyError: 'vala_COMPILER'

  Fixed by creating the Vala compile rules for all machines, not just
  the build machine.

1 files changed, 3 insertions, 0 deletions

diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 5855de7..86c1e33 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -1117,6 +1117,9 @@ class Compiler:
     def get_library_dirs(self, *args, **kwargs):
         return ()
 
+    def get_program_dirs(self, *args, **kwargs):
+        return ()
+
     def has_multi_arguments(self, args, env) -> Tuple[bool, bool]:
         raise EnvironmentException(
             'Language {} does not support has_multi_arguments.'.format(