Remove the always-true __INTRODUCED_IN() annotations.

The NDK no longer supports API levels earlier than 21.

This *doesn't* include <ctype.h> because I have a separate change
rewriting that (that's blocked on the upcoming libc++ update).

Test: treehugger
Change-Id: I53e915f27011dfc0513e0c78d8799377e183ceca
diff --git a/libc/include/bits/fortify/fcntl.h b/libc/include/bits/fortify/fcntl.h
index ce600ff..05c62eb 100644
--- a/libc/include/bits/fortify/fcntl.h
+++ b/libc/include/bits/fortify/fcntl.h
@@ -30,8 +30,8 @@
 #error "Never include this file directly; instead, include <fcntl.h>"
 #endif
 
-int __open_2(const char* _Nonnull, int) __INTRODUCED_IN(17);
-int __openat_2(int, const char* _Nonnull, int) __INTRODUCED_IN(17);
+int __open_2(const char* _Nonnull, int);
+int __openat_2(int, const char* _Nonnull, int);
 /*
  * These are the easiest way to call the real open even in clang FORTIFY.
  */
diff --git a/libc/include/bits/fortify/socket.h b/libc/include/bits/fortify/socket.h
index 8297580..02f94cc 100644
--- a/libc/include/bits/fortify/socket.h
+++ b/libc/include/bits/fortify/socket.h
@@ -32,8 +32,7 @@
 
 extern ssize_t __sendto_chk(int, const void* _Nonnull, size_t, size_t, int, const struct sockaddr* _Nullable,
         socklen_t) __INTRODUCED_IN(26);
-ssize_t __recvfrom_chk(int, void* _Nullable, size_t, size_t, int, struct sockaddr* _Nullable,
-        socklen_t* _Nullable) __INTRODUCED_IN(21);
+ssize_t __recvfrom_chk(int, void* _Nullable, size_t, size_t, int, struct sockaddr* _Nullable, socklen_t* _Nullable);
 
 #if defined(__BIONIC_FORTIFY)
 
diff --git a/libc/include/bits/fortify/stat.h b/libc/include/bits/fortify/stat.h
index 9b4ade2..378072c 100644
--- a/libc/include/bits/fortify/stat.h
+++ b/libc/include/bits/fortify/stat.h
@@ -28,7 +28,7 @@
 
 #pragma once
 
-mode_t __umask_chk(mode_t) __INTRODUCED_IN(18);
+mode_t __umask_chk(mode_t);
 mode_t __umask_real(mode_t mode) __RENAME(umask);
 
 #if defined(__BIONIC_FORTIFY)
diff --git a/libc/include/bits/fortify/stdio.h b/libc/include/bits/fortify/stdio.h
index 578d04c..e4607e0 100644
--- a/libc/include/bits/fortify/stdio.h
+++ b/libc/include/bits/fortify/stdio.h
@@ -30,7 +30,7 @@
 #error "Never include this file directly; instead, include <stdio.h>"
 #endif
 
-char* _Nullable __fgets_chk(char* _Nonnull, int, FILE* _Nonnull, size_t) __INTRODUCED_IN(17);
+char* _Nullable __fgets_chk(char* _Nonnull, int, FILE* _Nonnull, size_t);
 size_t __fread_chk(void* _Nonnull, size_t, size_t, FILE* _Nonnull, size_t) __INTRODUCED_IN(24);
 size_t __fwrite_chk(const void* _Nonnull, size_t, size_t, FILE* _Nonnull, size_t) __INTRODUCED_IN(24);
 
diff --git a/libc/include/bits/fortify/string.h b/libc/include/bits/fortify/string.h
index 3dc1cca..7df0b05 100644
--- a/libc/include/bits/fortify/string.h
+++ b/libc/include/bits/fortify/string.h
@@ -32,10 +32,10 @@
 
 void* _Nullable __memchr_chk(const void* _Nonnull, int, size_t, size_t) __INTRODUCED_IN(23);
 void* _Nullable __memrchr_chk(const void* _Nonnull, int, size_t, size_t) __INTRODUCED_IN(23);
-char* _Nonnull __stpncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t) __INTRODUCED_IN(21);
-char* _Nonnull __strncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t) __INTRODUCED_IN(21);
-size_t __strlcpy_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t) __INTRODUCED_IN(17);
-size_t __strlcat_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t) __INTRODUCED_IN(17);
+char* _Nonnull __stpncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t);
+char* _Nonnull __strncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t);
+size_t __strlcpy_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t);
+size_t __strlcat_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t);
 
 #if defined(__BIONIC_FORTIFY)
 extern void* _Nullable __memrchr_real(const void* _Nonnull, int, size_t) __RENAME(memrchr);
diff --git a/libc/include/bits/fortify/unistd.h b/libc/include/bits/fortify/unistd.h
index bbc228d..7eda1a6 100644
--- a/libc/include/bits/fortify/unistd.h
+++ b/libc/include/bits/fortify/unistd.h
@@ -43,7 +43,7 @@
 ssize_t __pwrite64_chk(int, const void* _Nonnull, size_t, off64_t, size_t) __INTRODUCED_IN(24);
 ssize_t __pwrite64_real(int, const void* _Nonnull, size_t, off64_t) __RENAME(pwrite64);
 
-ssize_t __read_chk(int, void* __BIONIC_COMPLICATED_NULLNESS, size_t, size_t) __INTRODUCED_IN(21);
+ssize_t __read_chk(int, void* __BIONIC_COMPLICATED_NULLNESS, size_t, size_t);
 ssize_t __write_chk(int, const void* __BIONIC_COMPLICATED_NULLNESS, size_t, size_t) __INTRODUCED_IN(24);
 ssize_t __readlink_chk(const char* _Nonnull, char* _Nonnull, size_t, size_t) __INTRODUCED_IN(23);
 ssize_t __readlinkat_chk(int dirfd, const char* _Nonnull, char* _Nonnull, size_t, size_t) __INTRODUCED_IN(23);
diff --git a/libc/include/bits/wctype.h b/libc/include/bits/wctype.h
index 3abbf82..11d5fde 100644
--- a/libc/include/bits/wctype.h
+++ b/libc/include/bits/wctype.h
@@ -39,7 +39,7 @@
 
 int iswalnum(wint_t __wc);
 int iswalpha(wint_t __wc);
-int iswblank(wint_t __wc) __INTRODUCED_IN(21);
+int iswblank(wint_t __wc);
 int iswcntrl(wint_t __wc);
 int iswdigit(wint_t __wc);
 int iswgraph(wint_t __wc);