API guard every post-21 API.

This was generated mechanically by reverting my recent re-hide commits
(except for mempcpy, but versioner cleaned that up for me anyway),
reverting the commits which removed versioner, then:

```
m out/soong/ndk_headers.timestamp
cp -r out/soong/ndk/sysroot/usr/include/* bionic/libc/include
git -C bionic clean -df
```

Effectively, this has restored the `versioner` processed headers, but
I'm checking the results of that in so we don't have to keep
`versioner` around.

For the NDK, this restores r27 behavior by default. Anyone that's
opted into weak APIs will get the new behavior. I think this is our
best option. Anyone writing code with Android in mind should be using
weak APIs, but any code being lightly ported (and thus using the
default configuration) should not be, and it's those ports where we're
having trouble with collisions.

Bug: https://github.com/android/ndk/issues/2081
Test: None
Change-Id: I370079d27566b0c1543fb5890c958c8d09b05006
diff --git a/libc/include/android/api-level.h b/libc/include/android/api-level.h
index 1bde3a5..c9536c1 100644
--- a/libc/include/android/api-level.h
+++ b/libc/include/android/api-level.h
@@ -189,7 +189,11 @@
  *
  * Available since API level 24.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(24)
 int android_get_application_target_sdk_version() __INTRODUCED_IN(24);
+#endif /* __BIONIC_AVAILABILITY_GUARD(24) */
+
 
 #if __ANDROID_API__ < 29
 
diff --git a/libc/include/android/crash_detail.h b/libc/include/android/crash_detail.h
index 490ec8c..fd1312a 100644
--- a/libc/include/android/crash_detail.h
+++ b/libc/include/android/crash_detail.h
@@ -80,6 +80,8 @@
  *
  * \return a handle to the extra crash detail.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(35)
 crash_detail_t* _Nullable android_crash_detail_register(
     const void* _Nonnull name, size_t name_size, const void* _Nullable data, size_t data_size) __INTRODUCED_IN(35);
 
@@ -123,5 +125,7 @@
  * \param name_size number of bytes of the buffer pointed to by name
  */
 void android_crash_detail_replace_name(crash_detail_t* _Nonnull crash_detail, const void* _Nonnull name, size_t name_size) __INTRODUCED_IN(35);
+#endif /* __BIONIC_AVAILABILITY_GUARD(35) */
+
 
 __END_DECLS
diff --git a/libc/include/android/fdsan.h b/libc/include/android/fdsan.h
index fd0a63f..a04fc7e 100644
--- a/libc/include/android/fdsan.h
+++ b/libc/include/android/fdsan.h
@@ -135,6 +135,8 @@
 /*
  * Create an owner tag with the specified type and least significant 56 bits of tag.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(29)
 uint64_t android_fdsan_create_owner_tag(enum android_fdsan_owner_type type, uint64_t tag) __INTRODUCED_IN(29) __attribute__((__weak__));
 
 /*
@@ -169,6 +171,8 @@
  * Get an owner tag's value, with the type masked off.
  */
 uint64_t android_fdsan_get_tag_value(uint64_t tag) __INTRODUCED_IN(29);
+#endif /* __BIONIC_AVAILABILITY_GUARD(29) */
+
 
 enum android_fdsan_error_level {
   // No errors.
@@ -187,6 +191,8 @@
 /*
  * Get the error level.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(29)
 enum android_fdsan_error_level android_fdsan_get_error_level() __INTRODUCED_IN(29) __attribute__((__weak__));
 
 /*
@@ -204,9 +210,15 @@
  * (e.g. postfork).
  */
 enum android_fdsan_error_level android_fdsan_set_error_level(enum android_fdsan_error_level new_level) __INTRODUCED_IN(29) __attribute__((__weak__));
+#endif /* __BIONIC_AVAILABILITY_GUARD(29) */
+
 
 /*
  * Set the error level to the global setting if available, or a default value.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(30)
 enum android_fdsan_error_level android_fdsan_set_error_level_from_property(enum android_fdsan_error_level default_level) __INTRODUCED_IN(30) __attribute__((__weak__));
+#endif /* __BIONIC_AVAILABILITY_GUARD(30) */
+
 __END_DECLS