Change bool, and string properties to *bool, and *string for cc

there's no use case for prepending/appending to bool, and string
properties within module struct. Declearing "*bool" and "*string" almost
cover everything user need.

I did see one case that user specify relative_install_path as
path prefix in cc_defaults, and concatenate with the one in real module
to get the final relative install path in Android.bp <bionic/tests/libs>.

Test: m -j checkbuild
Bug: b/68853585
Change-Id: If3a7a2689c3fc307aae136af6bc9c57f27a1e1a0
diff --git a/cc/object.go b/cc/object.go
index 2246dd3..d0f4f20 100644
--- a/cc/object.go
+++ b/cc/object.go
@@ -83,9 +83,9 @@
 	if len(objs.objFiles) == 1 {
 		outputFile = objs.objFiles[0]
 
-		if object.Properties.Prefix_symbols != "" {
+		if String(object.Properties.Prefix_symbols) != "" {
 			output := android.PathForModuleOut(ctx, ctx.ModuleName()+objectExtension)
-			TransformBinaryPrefixSymbols(ctx, object.Properties.Prefix_symbols, outputFile,
+			TransformBinaryPrefixSymbols(ctx, String(object.Properties.Prefix_symbols), outputFile,
 				builderFlags, output)
 			outputFile = output
 		}
@@ -93,9 +93,9 @@
 		output := android.PathForModuleOut(ctx, ctx.ModuleName()+objectExtension)
 		outputFile = output
 
-		if object.Properties.Prefix_symbols != "" {
+		if String(object.Properties.Prefix_symbols) != "" {
 			input := android.PathForModuleOut(ctx, "unprefixed", ctx.ModuleName()+objectExtension)
-			TransformBinaryPrefixSymbols(ctx, object.Properties.Prefix_symbols, input,
+			TransformBinaryPrefixSymbols(ctx, String(object.Properties.Prefix_symbols), input,
 				builderFlags, output)
 			output = input
 		}