Add soong_build primary builder

Initial build logic for building android with soong.  It can build
a variety of C and C++ files for arm/arm64 and host.

Change-Id: I10eb37c2c2a50be6af1bb5fd568c0962b9476bf0

common/defs.go

@@ -0,0 +1,61 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// 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.
+
+package common
+
+import (
+	"blueprint"
+)
+
+var (
+	pctx = blueprint.NewPackageContext("android/soong/common")
+
+	cpPreserveSymlinks = pctx.VariableConfigMethod("cpPreserveSymlinks",
+		Config.CpPreserveSymlinksFlags)
+
+	// A phony rule that is not the built-in Ninja phony rule.  The built-in
+	// phony rule has special behavior that is sometimes not desired.  See the
+	// Ninja docs for more details.
+	Phony = pctx.StaticRule("Phony",
+		blueprint.RuleParams{
+			Command:     "# phony $out",
+			Description: "phony $out",
+		})
+
+	// GeneratedFile is a rule for indicating that a given file was generated
+	// while running soong.  This allows the file to be cleaned up if it ever
+	// stops being generated by soong.
+	GeneratedFile = pctx.StaticRule("GeneratedFile",
+		blueprint.RuleParams{
+			Command:     "# generated $out",
+			Description: "generated $out",
+			Generator:   true,
+		})
+
+	// A copy rule.
+	Cp = pctx.StaticRule("Cp",
+		blueprint.RuleParams{
+			Command:     "cp $cpPreserveSymlinks $cpFlags $in $out",
+			Description: "cp $out",
+		},
+		"cpFlags")
+
+	// A symlink rule.
+	Symlink = pctx.StaticRule("Symlink",
+		blueprint.RuleParams{
+			Command:     "ln -f -s $fromPath $out",
+			Description: "symlink $out",
+		},
+		"fromPath")
+)