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/toolchain_library.go b/cc/toolchain_library.go
index 9b83f18..2bb4018 100644
--- a/cc/toolchain_library.go
+++ b/cc/toolchain_library.go
@@ -15,8 +15,6 @@
 package cc
 
 import (
-	"github.com/google/blueprint/proptools"
-
 	"android/soong/android"
 )
 
@@ -45,7 +43,7 @@
 	}
 	module.compiler = toolchainLibrary
 	module.linker = toolchainLibrary
-	module.Properties.Clang = proptools.BoolPtr(false)
+	module.Properties.Clang = BoolPtr(false)
 	module.stl = nil
 	module.sanitize = nil
 	module.installer = nil