Update static functions/macro definitions.

Fix the list of static functions coming from swab.h to match the
ones exported by glibc.

Force the definition of __HAVE_BUILTIN_BSWAP{16,32,64}__ so the headers
use the builtin.

Add a unit test to guarantee that kernel header updates do not break this.

Test: Built and booted angler.
Test: Built the bionic unit tests for arm, arm64, mips, x86, x86_64.
Test: Ran the new test on angler and glibc.

Change-Id: I4ce229e3f198c204186d72bf22dd97b5cdf239e4
diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index 620bb31..c22f684 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -26,6 +26,9 @@
     "CONFIG_64BIT": "__LP64__",
     "CONFIG_X86_32": "__i386__",
     "__EXPORTED_HEADERS__": "1",
+    "__HAVE_BUILTIN_BSWAP16__": "1",
+    "__HAVE_BUILTIN_BSWAP32__": "1",
+    "__HAVE_BUILTIN_BSWAP64__": "1",
     }
 
 # define to true if you want to remove all defined(CONFIG_FOO) tests
@@ -77,14 +80,14 @@
     "udphdr": "__kernel_udphdr",
     # The kernel's struct epoll_event just has __u64 for the data.
     "epoll_event": "__kernel_uapi_epoll_event",
+    # This causes problems when trying to export the headers for the ndk.
+    "__attribute_const__": "__attribute__((__const__))",
     }
 
-# 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.
-# TODO: this isn't working!
+# This is the set of known static inline functions that we want to keep
+# in the final kernel headers.
 kernel_known_arm_statics = set(
-        [ "___arch__swab32",    # asm-arm/byteorder.h
+        [
         ]
     )
 
@@ -99,8 +102,7 @@
     )
 
 kernel_known_x86_statics = set(
-        [ "___arch__swab32",  # asm-x86/byteorder.h
-          "___arch__swab64",  # asm-x86/byteorder.h
+        [
         ]
     )
 
@@ -108,6 +110,26 @@
         [
           "ipt_get_target",  # uapi/linux/netfilter_ipv4/ip_tables.h
           "ip6t_get_target", # uapi/linux/netfilter_ipv6/ip6_tables.h
+          # Byte swapping inlines from uapi/linux/swab.h
+          # The below functions are the ones we are guaranting we export.
+          "__swab16",
+          "__swab32",
+          "__swab64",
+          "__swab16p",
+          "__swab32p",
+          "__swab64p",
+          "__swab16s",
+          "__swab32s",
+          "__swab64s",
+          "__swahw32",
+          "__swahb32",
+          "__swahw32p",
+          "__swahb32p",
+          "__swahw32s",
+          "__swahb32s",
+          # These are required to support the above functions.
+          "__fswahw32",
+          "__fswahb32",
         ]
     )