extension: add hawkmoth_clang_c and hawkmoth_clang_cpp config options

Add config options hawkmoth_clang_c and hawkmoth_clang_cpp to pass
arguments to clang in the C and C++ domains, respectively.

Fixes #255

CHANGELOG.rst

@@ -6,6 +6,12 @@ Unreleased `master`_
 
 :Date: YYYY-MM-DD
 
+Added
+~~~~~
+
+* Domain specific config options ``hawkmoth_clang_c`` and
+  ``hawkmoth_clang_cpp``.
+
 Changed
 ~~~~~~~
 

doc/extension.rst

@@ -85,6 +85,18 @@ See also additional configuration options in the :ref:`built-in extensions
    You can also pass in the compiler to use, for example
    ``get_include_args('gcc')``.
 
+.. py:data:: hawkmoth_clang_c
+   :type: list
+
+   Arguments to pass to ``clang`` after :data:`hawkmoth_clang` in the C domain
+   only.
+
+.. py:data:: hawkmoth_clang_cpp
+   :type: list
+
+   Arguments to pass to ``clang`` after :data:`hawkmoth_clang` in the C++ domain
+   only.
+
 .. py:data:: hawkmoth_source_uri
    :type: str
 

src/hawkmoth/__init__.py

@@ -57,6 +57,11 @@ def __get_clang_args(self):
 
         clang_args.extend(self.env.config.hawkmoth_clang.copy())
 
+        if self._domain == 'c':
+            clang_args.extend(self.env.config.hawkmoth_clang_c.copy())
+        else:
+            clang_args.extend(self.env.config.hawkmoth_clang_cpp.copy())
+
         clang_args.extend(self.options.get('clang', []))
 
         return clang_args
@@ -353,6 +358,8 @@ def setup(app):
 
     app.add_config_value('hawkmoth_root', app.confdir, 'env', [str])
     app.add_config_value('hawkmoth_clang', [], 'env', [list])
+    app.add_config_value('hawkmoth_clang_c', [], 'env', [list])
+    app.add_config_value('hawkmoth_clang_cpp', [], 'env', [list])
 
     app.add_config_value('hawkmoth_transform_default', None, 'env', [str])