Disable building libapplypatch on mac

The sdk_mac on build server fails with the error:
bootable/recovery/applypatch/freecache.cpp:23:10: fatal error: 'sys/statfs.h' file not found

So we will disable libapplypatch on mac.

Test: the library still builds on linux; and check the other host targets in the same cl.
Change-Id: Ie4a30708726e51c810f7ad7f1085d38154076cca

applypatch/Android.bp

@@ -57,6 +57,12 @@ cc_library_static {
         "libotautil",
         "libz",
     ],
+
+    target: {
+        darwin: {
+            enabled: false,
+        },
+    },
 }
 
 cc_library_static {

otafault/Android.bp

@@ -39,6 +39,12 @@ cc_library_static {
         "-Wthread-safety",
         "-Wthread-safety-negative",
     ],
+
+    target: {
+        darwin: {
+            enabled: false,
+        },
+    },
 }
 
 cc_test {