Support rtti in bp2build

Rtti was already handled by bazel macros, so this change simply
propagates the rtti bit to these macros.

Test: Run bp2build, build //external/libcxxabi:all
Change-Id: I63296db2db868202874c8bd0b1de6310f7bb85c7
diff --git a/cc/bp2build.go b/cc/bp2build.go
index 7a57477..1706d72 100644
--- a/cc/bp2build.go
+++ b/cc/bp2build.go
@@ -240,6 +240,8 @@
 	// C++ options and sources
 	cppFlags bazel.StringListAttribute
 	srcs     bazel.LabelListAttribute
+
+	rtti bazel.BoolAttribute
 }
 
 // bp2BuildParseCompilerProps returns copts, srcs and hdrs and other attributes.
@@ -249,6 +251,7 @@
 	var asFlags bazel.StringListAttribute
 	var conlyFlags bazel.StringListAttribute
 	var cppFlags bazel.StringListAttribute
+	var rtti bazel.BoolAttribute
 
 	// Creates the -I flags for a directory, while making the directory relative
 	// to the exec root for Bazel to work.
@@ -302,6 +305,7 @@
 			asFlags.Value = parseCommandLineFlags(baseCompilerProps.Asflags)
 			conlyFlags.Value = parseCommandLineFlags(baseCompilerProps.Conlyflags)
 			cppFlags.Value = parseCommandLineFlags(baseCompilerProps.Cppflags)
+			rtti.Value = baseCompilerProps.Rtti
 
 			for _, dir := range parseLocalIncludeDirs(baseCompilerProps) {
 				copts.Value = append(copts.Value, includeFlags(dir)...)
@@ -345,6 +349,7 @@
 				asFlags.SetSelectValue(axis, config, archVariantAsflags)
 				conlyFlags.SetSelectValue(axis, config, parseCommandLineFlags(baseCompilerProps.Conlyflags))
 				cppFlags.SetSelectValue(axis, config, parseCommandLineFlags(baseCompilerProps.Cppflags))
+				rtti.SetSelectValue(axis, config, baseCompilerProps.Rtti)
 			}
 		}
 	}
@@ -380,6 +385,7 @@
 		cSrcs:      cSrcs,
 		conlyFlags: conlyFlags,
 		cppFlags:   cppFlags,
+		rtti:       rtti,
 	}
 }