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/installer.go b/cc/installer.go
index 92076e5..33f29f2 100644
--- a/cc/installer.go
+++ b/cc/installer.go
@@ -24,7 +24,7 @@
 
 type InstallerProperties struct {
 	// install to a subdirectory of the default install path for the module
-	Relative_install_path string `android:"arch_variant"`
+	Relative_install_path *string `android:"arch_variant"`
 }
 
 type installLocation int
@@ -72,7 +72,8 @@
 	if installer.location == InstallInData && ctx.useVndk() {
 		dir = filepath.Join(dir, "vendor")
 	}
-	return android.PathForModuleInstall(ctx, dir, installer.subDir, installer.Properties.Relative_install_path, installer.relative)
+	return android.PathForModuleInstall(ctx, dir, installer.subDir,
+		String(installer.Properties.Relative_install_path), installer.relative)
 }
 
 func (installer *baseInstaller) install(ctx ModuleContext, file android.Path) {