disable rtti by default even for non-bionic builds

With this change, we'll use same the logic to determine whether to
disable RTTI for all targets. Previously, there was no way to disable
RTTI for glibc or musl host builds.

Bug: 341341056
Test: m
Change-Id: I096ddf54314c7692d4a82f549e2071471a6c72f3
diff --git a/cc/compiler.go b/cc/compiler.go
index ede6a5d..5ff6e3a 100644
--- a/cc/compiler.go
+++ b/cc/compiler.go
@@ -549,12 +549,10 @@
 		flags.Global.CommonFlags = append(flags.Global.CommonFlags, "${config.ExternalCflags}")
 	}
 
-	if tc.Bionic() {
-		if Bool(compiler.Properties.Rtti) {
-			flags.Local.CppFlags = append(flags.Local.CppFlags, "-frtti")
-		} else {
-			flags.Local.CppFlags = append(flags.Local.CppFlags, "-fno-rtti")
-		}
+	if Bool(compiler.Properties.Rtti) {
+		flags.Local.CppFlags = append(flags.Local.CppFlags, "-frtti")
+	} else {
+		flags.Local.CppFlags = append(flags.Local.CppFlags, "-fno-rtti")
 	}
 
 	flags.Global.AsFlags = append(flags.Global.AsFlags, "${config.CommonGlobalAsflags}")