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/time.h b/libc/include/time.h
index e9d6569..6c9b761 100644
--- a/libc/include/time.h
+++ b/libc/include/time.h
@@ -166,7 +166,11 @@
  *
  * Available since API level 35.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(35)
 time_t mktime_z(timezone_t _Nonnull __tz, struct tm* _Nonnull __tm) __INTRODUCED_IN(35);
+#endif /* __BIONIC_AVAILABILITY_GUARD(35) */
+
 
 /**
  * [localtime(3)](https://man7.org/linux/man-pages/man3/localtime.3p.html) converts
@@ -200,7 +204,11 @@
  *
  * Available since API level 35.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(35)
 struct tm* _Nullable localtime_rz(timezone_t _Nonnull __tz, const time_t* _Nonnull __t, struct tm* _Nonnull __tm) __INTRODUCED_IN(35);
+#endif /* __BIONIC_AVAILABILITY_GUARD(35) */
+
 
 /**
  * Inverse of localtime().
@@ -314,6 +322,8 @@
  *
  * Available since API level 35.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(35)
 timezone_t _Nullable tzalloc(const char* _Nullable __id) __INTRODUCED_IN(35);
 
 /**
@@ -326,6 +336,8 @@
  * Available since API level 35.
  */
 void tzfree(timezone_t _Nullable __tz) __INTRODUCED_IN(35);
+#endif /* __BIONIC_AVAILABILITY_GUARD(35) */
+
 
 /**
  * [clock(3)](https://man7.org/linux/man-pages/man3/clock.3.html)
@@ -345,7 +357,11 @@
  *
  * Returns 0 on success, and returns -1 and returns an error number on failure.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(23)
 int clock_getcpuclockid(pid_t __pid, clockid_t* _Nonnull __clock) __INTRODUCED_IN(23);
+#endif /* __BIONIC_AVAILABILITY_GUARD(23) */
+
 
 /**
  * [clock_getres(2)](https://man7.org/linux/man-pages/man2/clock_getres.2.html)
@@ -459,7 +475,11 @@
  * Available since API level 29 for TIME_UTC; other bases arrived later.
  * Code for Android should prefer clock_gettime().
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(29)
 int timespec_get(struct timespec* _Nonnull __ts, int __base) __INTRODUCED_IN(29);
+#endif /* __BIONIC_AVAILABILITY_GUARD(29) */
+
 
 /**
  * timespec_getres(3) is equivalent to clock_getres() for the clock corresponding to the given base.
@@ -469,6 +489,10 @@
  * Available since API level 35.
  * Code for Android should prefer clock_gettime().
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(35)
 int timespec_getres(struct timespec* _Nonnull __ts, int __base) __INTRODUCED_IN(35);
+#endif /* __BIONIC_AVAILABILITY_GUARD(35) */
+
 
 __END_DECLS