Tweaked the cleanup scripts to handle uapi and aarch64 headers.

The processed uapi directory is now placed at libc/kernel/uapi as
opposed to libc/kernel/common/uapi as it contains
architectural-dependent headers now.

Change-Id: I53f814704a4d231b452fde398cd94257a0fb2eea
diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index 77bfc47..3968605 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -7,7 +7,7 @@
 
 # the list of supported architectures
 #
-kernel_archs = [ 'arm', 'mips', 'x86' ]
+kernel_archs = [ 'aarch64', 'arm', 'mips', 'x86' ]
 
 # the list of include directories that belong to the kernel
 # tree. used when looking for sources...
@@ -44,12 +44,14 @@
 # maps an architecture to a set of default macros that would be provided by
 # toolchain preprocessor
 kernel_default_arch_macros = {
+    "aarch64": {},
     "arm": {},
     "mips": {"CONFIG_32BIT":"1"},
     "x86": {},
     }
 
 kernel_arch_token_replacements = {
+    "aarch64": {},
     "arm": {},
     "mips": {"off_t":"__kernel_off_t"},
     "x86": {},
@@ -63,6 +65,11 @@
 # this is the set of known static inline functions that we want to keep
 # in the final ARM headers. this is only used to keep optimized byteswapping
 # static functions and stuff like that.
+kernel_known_aarch64_statics = set(
+        [
+        ]
+    )
+
 kernel_known_arm_statics = set(
         [ "___arch__swab32",    # asm-arm/byteorder.h
         ]
@@ -92,6 +99,7 @@
 # we want to keep in the final headers
 #
 kernel_known_statics = {
+        "aarch64" : kernel_known_aarch64_statics,
         "arm" : kernel_known_arm_statics,
         "mips" : kernel_known_mips_statics,
         "x86" : kernel_known_x86_statics,