added c2hal

This is a transpiler which converts C headers to .hal files. Its design
is intended to mirror hidl-gen in order to make it easier for team
members familiar with one to be familiar with the other.

After making c2hal, commands from ~/android/master/:

Build the test.h header:
c2hal -r android.hardware:hardware/interfaces -p android.hardware.baz@1.0 system/tools/hidl/c2hal/test/test.h

Build the simple.h header:
c2hal -r android.hardware:hardware/interfaces -p android.hardware.simple@1.0 system/tools/hidl/c2hal/test/simple.h

Build all headers from libhardware:
python3 system/tools/hidl/c2hal/test/build_all.py ~/android/master/hardware/libhardware/include/hardware/

Build various OpenGl versions:
python3 system/tools/hidl/c2hal/test/build_all.py -g ~/android/master/frameworks/native/opengl/include/EGL/
python3 system/tools/hidl/c2hal/test/build_all.py -g ~/android/master/frameworks/native/opengl/include/ETC1/
python3 system/tools/hidl/c2hal/test/build_all.py -g ~/android/master/frameworks/native/opengl/include/GLES/
python3 system/tools/hidl/c2hal/test/build_all.py -g ~/android/master/frameworks/native/opengl/include/GLES2/
python3 system/tools/hidl/c2hal/test/build_all.py -g ~/android/master/frameworks/native/opengl/include/GLES3/
python3 system/tools/hidl/c2hal/test/build_all.py -g ~/android/master/frameworks/native/opengl/include/KHR/

Change-Id: I5a3b1d6d2350dd7e1ff825deeec212314b49d083
diff --git a/c2hal/Define.h b/c2hal/Define.h
new file mode 100644
index 0000000..e66159d
--- /dev/null
+++ b/c2hal/Define.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef DEFINE_H_
+#define DEFINE_H_
+
+#include <android-base/macros.h>
+#include <android-base/logging.h>
+#include <string>
+#include <vector>
+#include "Declaration.h"
+#include "Expression.h"
+
+namespace android {
+
+struct Define : Declaration {
+    Define(const std::string &name, const std::string &slurp);
+    ~Define();
+
+    static std::string type() { return "define"; }
+    const std::string decType() const override { return type(); }
+
+    void generateSource(Formatter &out) const override;
+    void processContents(AST &ast) override;
+
+    Expression::Type getExpressionType() const;
+    Expression *getExpression() const;
+    void setExpression(Expression* expression);
+
+private:
+    const std::string mSlurp;
+
+    Expression::Type mExpressionType;
+    Expression* mExpression = NULL;
+
+    DISALLOW_COPY_AND_ASSIGN(Define);
+};
+
+}  // namespace android
+
+#endif  // DEFINE_H_
\ No newline at end of file