kill OS_CASE_SENSITIVE

Bug: 18314594
Change-Id: Ib11b45d2597b2576bc7df2d0167ce1bbd1449523
diff --git a/tools/aidl/aidl.cpp b/tools/aidl/aidl.cpp
index 45dd23b..14c9f95 100644
--- a/tools/aidl/aidl.cpp
+++ b/tools/aidl/aidl.cpp
@@ -228,7 +228,8 @@
         }
 #endif
 
-#ifdef OS_CASE_SENSITIVE
+        // aidl assumes case-insensitivity on Mac Os and Windows.
+#if defined(__linux__)
         valid = (expected == p);
 #else
         valid = !strcasecmp(expected.c_str(), p);