libc/include: remove easy __ANDROID_API__ tautologies.

The next NDK to take these headers only supports API 21 and later, so
clean up some of the trivial cruft.

This doesn't include the remaining "legacy inlines", since they're a bit
more complicated. I'll remove those in later changes.

Test: treehugger
Change-Id: I94c32f6393dd3ae831165917303ea591222baa0d
diff --git a/libc/include/bits/fortify/fcntl.h b/libc/include/bits/fortify/fcntl.h
index 7fe60f4..1f6ebad 100644
--- a/libc/include/bits/fortify/fcntl.h
+++ b/libc/include/bits/fortify/fcntl.h
@@ -59,7 +59,7 @@
 int open(const char* const __pass_object_size pathname, int flags)
         __overloadable
         __clang_error_if(__open_modes_useful(flags), "'open' " __open_too_few_args_error) {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __open_2(pathname, flags);
 #else
     return __open_real(pathname, flags);
@@ -83,7 +83,7 @@
 int openat(int dirfd, const char* const __pass_object_size pathname, int flags)
         __overloadable
         __clang_error_if(__open_modes_useful(flags), "'openat' " __open_too_few_args_error) {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __openat_2(dirfd, pathname, flags);
 #else
     return __openat_real(dirfd, pathname, flags);
@@ -98,7 +98,6 @@
     return __openat_real(dirfd, pathname, flags, modes);
 }
 
-#if __ANDROID_API__ >= 21
 /* Note that open == open64, so we reuse those bits in the open64 variants below.  */
 
 __BIONIC_ERROR_FUNCTION_VISIBILITY
@@ -139,7 +138,6 @@
                            "'openat64' " __open_useless_modes_warning) {
     return openat(dirfd, pathname, flags, modes);
 }
-#endif /* __ANDROID_API__ >= 21 */
 
 #undef __open_too_many_args_error
 #undef __open_too_few_args_error
diff --git a/libc/include/bits/fortify/poll.h b/libc/include/bits/fortify/poll.h
index 143153c..0b5cd4b 100644
--- a/libc/include/bits/fortify/poll.h
+++ b/libc/include/bits/fortify/poll.h
@@ -54,7 +54,6 @@
   return __call_bypassing_fortify(poll)(fds, fd_count, timeout);
 }
 
-#if __ANDROID_API__ >= 21
 __BIONIC_FORTIFY_INLINE
 int ppoll(struct pollfd* const fds __pass_object_size, nfds_t fd_count, const struct timespec* timeout, const sigset_t* mask)
     __overloadable
@@ -69,7 +68,6 @@
 #endif
   return __call_bypassing_fortify(ppoll)(fds, fd_count, timeout, mask);
 }
-#endif /* __ANDROID_API__ >= 21 */
 
 #if __ANDROID_API__ >= 28
 __BIONIC_FORTIFY_INLINE
diff --git a/libc/include/bits/fortify/stat.h b/libc/include/bits/fortify/stat.h
index 2d42a51..9b4ade2 100644
--- a/libc/include/bits/fortify/stat.h
+++ b/libc/include/bits/fortify/stat.h
@@ -39,7 +39,7 @@
     __overloadable
     __enable_if(1, "")
     __clang_error_if(mode & ~0777, "'umask' called with invalid mode") {
-#if __ANDROID_API__ >= 18 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
   return __umask_chk(mode);
 #else
   return __umask_real(mode);
diff --git a/libc/include/bits/fortify/stdio.h b/libc/include/bits/fortify/stdio.h
index 77bdbb4..95db017 100644
--- a/libc/include/bits/fortify/stdio.h
+++ b/libc/include/bits/fortify/stdio.h
@@ -36,7 +36,7 @@
 
 #if defined(__BIONIC_FORTIFY) && !defined(__BIONIC_NO_STDIO_FORTIFY)
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE __printflike(3, 0)
 int vsnprintf(char* const __pass_object_size dest, size_t size, const char* format, va_list ap)
@@ -58,7 +58,7 @@
                 "format string will always overflow destination buffer")
     __errorattr("format string will always overflow destination buffer");
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 __BIONIC_FORTIFY_VARIADIC __printflike(2, 3)
 int sprintf(char* const __pass_object_size dest, const char* format, ...) __overloadable {
     va_list va;
@@ -126,7 +126,7 @@
         __clang_error_if(size < 0, "in call to 'fgets', size should not be negative")
         __clang_error_if(__bos_unevaluated_lt(__bos(dest), size),
                          "in call to 'fgets', size is larger than the destination buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos(dest);
 
     if (!__bos_dynamic_check_impl_and(bos, >=, (size_t)size, size >= 0)) {
diff --git a/libc/include/bits/fortify/string.h b/libc/include/bits/fortify/string.h
index 08bce2d..f668b9f 100644
--- a/libc/include/bits/fortify/string.h
+++ b/libc/include/bits/fortify/string.h
@@ -40,7 +40,7 @@
 #if defined(__BIONIC_FORTIFY)
 extern void* __memrchr_real(const void*, int, size_t) __RENAME(memrchr);
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE
 void* memcpy(void* const dst __pass_object_size0, const void* src, size_t copy_amount)
@@ -82,7 +82,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_le(__bos(dst), __builtin_strlen(src)),
                          "'stpcpy' called with string bigger than buffer") {
-#if __ANDROID_API__ >= 21 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___stpcpy_chk(dst, src, __bos(dst));
 #else
     return __builtin_stpcpy(dst, src);
@@ -95,7 +95,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_le(__bos(dst), __builtin_strlen(src)),
                          "'strcpy' called with string bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___strcpy_chk(dst, src, __bos(dst));
 #else
     return __builtin_strcpy(dst, src);
@@ -107,14 +107,14 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_le(__bos(dst), __builtin_strlen(src)),
                          "'strcat' called with string bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___strcat_chk(dst, src, __bos(dst));
 #else
     return __builtin_strcat(dst, src);
 #endif
 }
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE
 char* strncat(char* const dst __pass_object_size, const char* src, size_t n)
@@ -130,7 +130,7 @@
         __diagnose_as_builtin(__builtin_memset, 1, 2, 3)
         /* If you're a user who wants this warning to go away: use `(&memset)(foo, bar, baz)`. */
         __clang_warning_if(c && !n, "'memset' will set 0 bytes; maybe the arguments got flipped?") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __builtin___memset_chk(s, c, n, __bos0(s));
 #else
     return __builtin_memset(s, c, n);
@@ -161,7 +161,7 @@
 }
 #endif
 
-#if __ANDROID_API__ >= 21 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 /* No diag -- clang diagnoses misuses of this on its own.  */
 __BIONIC_FORTIFY_INLINE
 char* stpncpy(char* const dst __pass_object_size, const char* const src __pass_object_size, size_t n)
@@ -200,7 +200,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos(dst), size),
                          "'strlcpy' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __strlcpy_chk(dst, src, size, __bos(dst));
 #else
     return __call_bypassing_fortify(strlcpy)(dst, src, size);
@@ -212,14 +212,14 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos(dst), size),
                          "'strlcat' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     return __strlcat_chk(dst, src, size, __bos(dst));
 #else
     return __call_bypassing_fortify(strlcat)(dst, src, size);
 #endif
 }
 
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
 __BIONIC_FORTIFY_INLINE
 size_t strlen(const char* const s __pass_object_size0) __overloadable {
     return __strlen_chk(s, __bos0(s));
@@ -228,7 +228,7 @@
 
 __BIONIC_FORTIFY_INLINE
 char* strchr(const char* const s __pass_object_size, int c) __overloadable {
-#if  __ANDROID_API__ >= 18 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos(s);
 
     if (bos != __BIONIC_FORTIFY_UNKNOWN_SIZE) {
@@ -240,7 +240,7 @@
 
 __BIONIC_FORTIFY_INLINE
 char* strrchr(const char* const s __pass_object_size, int c) __overloadable {
-#if  __ANDROID_API__ >= 18 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos(s);
 
     if (bos != __BIONIC_FORTIFY_UNKNOWN_SIZE) {
diff --git a/libc/include/bits/fortify/strings.h b/libc/include/bits/fortify/strings.h
index 65fc5f1..5515ef9 100644
--- a/libc/include/bits/fortify/strings.h
+++ b/libc/include/bits/fortify/strings.h
@@ -33,7 +33,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos0(dst), len),
                          "'bcopy' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos0(dst);
     if (!__bos_trivially_ge(bos, len)) {
         __builtin___memmove_chk(dst, src, len, bos);
@@ -48,7 +48,7 @@
         __overloadable
         __clang_error_if(__bos_unevaluated_lt(__bos0(b), len),
                          "'bzero' called with size bigger than buffer") {
-#if __ANDROID_API__ >= 17 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos0(b);
     if (!__bos_trivially_ge(bos, len)) {
         __builtin___memset_chk(b, 0, len, bos);
diff --git a/libc/include/bits/fortify/unistd.h b/libc/include/bits/fortify/unistd.h
index 49a3946..335d0b5 100644
--- a/libc/include/bits/fortify/unistd.h
+++ b/libc/include/bits/fortify/unistd.h
@@ -152,7 +152,7 @@
         __overloadable
         __error_if_overflows_ssizet(count, read)
         __error_if_overflows_objectsize(count, __bos0(buf), read) {
-#if __ANDROID_API__ >= 21 && __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
+#if __BIONIC_FORTIFY_RUNTIME_CHECKS_ENABLED
     size_t bos = __bos0(buf);
 
     if (!__bos_trivially_ge_no_overflow(bos, count)) {
@@ -192,7 +192,6 @@
     return __call_bypassing_fortify(readlink)(path, buf, size);
 }
 
-#if __ANDROID_API__ >= 21
 __BIONIC_FORTIFY_INLINE
 ssize_t readlinkat(int dirfd, const char* path, char* const __pass_object_size buf, size_t size)
         __overloadable
@@ -207,7 +206,6 @@
 #endif
     return __call_bypassing_fortify(readlinkat)(dirfd, path, buf, size);
 }
-#endif /* __ANDROID_API__ >= 21 */
 
 #undef __bos_trivially_ge_no_overflow
 #undef __enable_if_no_overflow_ssizet