Undo recent _FILE_OFFSET_BITS=64 changes.

We had several bugs filed saying "if I set _FILE_OFFSET_BITS=64 when
targeting an API < L, various functions are missing". Instead of
saying "yes, they are", we quietly just modified the header files to
expose the non-64-bit variants. This makes no sense. We can't just say
"oh, yeah, we don't have a version of this function that agrees with
your calling code about how large off_t is, but here's a version that
doesn't: I'm sure it'll be fine".

_FILE_OFFSET_BITS=64 on Android LP32 has always been a game of chance,
but that game should be "are all the functions my code needs available
at compile time?", not "will my code actually work at run time?".

Bug: android/ndk#442
Bug: android/ndk#333
Bug: android/ndk#332
Bug: android/ndk#324
Test: builds
Change-Id: Ib095251d3e21e77ed50cc3575388107fecec4ecd

libc/include/bits/lockf.h

@@ -40,7 +40,7 @@
 __BEGIN_DECLS
 
 #if defined(__USE_FILE_OFFSET64)
-int lockf(int, int, off_t) __RENAME(lockf64);
+int lockf(int, int, off_t) __RENAME(lockf64) __INTRODUCED_IN(24);
 #else
 int lockf(int, int, off_t) __INTRODUCED_IN(24);
 #endif

libc/include/stdio.h

@@ -176,17 +176,17 @@ int renameat(int, const char*, int, const char*);
 int fseek(FILE*, long, int);
 long ftell(FILE*);
 
-#if defined(__USE_FILE_OFFSET64) && __ANDROID_API__ >= __ANDROID_API_N__
-int fgetpos(FILE*, fpos_t*) __RENAME(fgetpos64);
-int fsetpos(FILE*, const fpos_t*) __RENAME(fsetpos64);
-int fseeko(FILE*, off_t, int) __RENAME(fseeko64);
-off_t ftello(FILE*) __RENAME(ftello64);
+#if defined(__USE_FILE_OFFSET64)
+int fgetpos(FILE*, fpos_t*) __RENAME(fgetpos64) __INTRODUCED_IN(24);
+int fsetpos(FILE*, const fpos_t*) __RENAME(fsetpos64) __INTRODUCED_IN(24);
+int fseeko(FILE*, off_t, int) __RENAME(fseeko64) __INTRODUCED_IN(24);
+off_t ftello(FILE*) __RENAME(ftello64) __INTRODUCED_IN(24);
 #  if defined(__USE_BSD)
 FILE* funopen(const void*,
               int (*)(void*, char*, int),
               int (*)(void*, const char*, int),
               fpos_t (*)(void*, fpos_t, int),
-              int (*)(void*)) __RENAME(funopen64);
+              int (*)(void*)) __RENAME(funopen64) __INTRODUCED_IN(24);
 #  endif
 #else
 int fgetpos(FILE*, fpos_t*);

libc/include/sys/mman.h

@@ -43,7 +43,7 @@ __BEGIN_DECLS
 #define MREMAP_MAYMOVE  1
 #define MREMAP_FIXED    2
 
-#if defined(__USE_FILE_OFFSET64) && __ANDROID_API__ >= __ANDROID_API_L__
+#if defined(__USE_FILE_OFFSET64)
 void* mmap(void*, size_t, int, int, int, off_t) __RENAME(mmap64) __INTRODUCED_IN(21);
 #else
 void* mmap(void*, size_t, int, int, int, off_t);
@@ -71,7 +71,7 @@ int madvise(void*, size_t, int);
  * Some third-party code uses the existence of POSIX_MADV_NORMAL to detect the
  * availability of posix_madvise. This is not correct, since having up-to-date
  * UAPI headers says nothing about the C library, but for the time being we
- * don't want to harm adoption to the unified headers.
+ * don't want to harm adoption of the unified headers.
  *
  * https://github.com/android-ndk/ndk/issues/395
  */

libc/include/sys/sendfile.h

@@ -34,9 +34,8 @@
 
 __BEGIN_DECLS
 
-#if defined(__USE_FILE_OFFSET64) && __ANDROID_API__ >= __ANDROID_API_L__
-ssize_t sendfile(int out_fd, int in_fd, off_t* offset, size_t count) __RENAME(sendfile64)
-  __INTRODUCED_IN(21);
+#if defined(__USE_FILE_OFFSET64)
+ssize_t sendfile(int out_fd, int in_fd, off_t* offset, size_t count) __RENAME(sendfile64) __INTRODUCED_IN(21);
 #else
 ssize_t sendfile(int out_fd, int in_fd, off_t* offset, size_t count);
 #endif

libc/include/sys/uio.h

@@ -39,8 +39,8 @@ ssize_t writev(int, const struct iovec*, int);
 
 #if defined(__USE_GNU)
 #if defined(__USE_FILE_OFFSET64)
-ssize_t preadv(int, const struct iovec*, int, off_t) __RENAME(preadv64);
-ssize_t pwritev(int, const struct iovec*, int, off_t) __RENAME(pwritev64);
+ssize_t preadv(int, const struct iovec*, int, off_t) __RENAME(preadv64) __INTRODUCED_IN(24);
+ssize_t pwritev(int, const struct iovec*, int, off_t) __RENAME(pwritev64) __INTRODUCED_IN(24);
 #else
 ssize_t preadv(int, const struct iovec*, int, off_t) __INTRODUCED_IN(24);
 ssize_t pwritev(int, const struct iovec*, int, off_t) __INTRODUCED_IN(24);

libc/include/unistd.h

@@ -173,7 +173,7 @@ off_t lseek(int __fd, off_t __offset, int __whence);
 
 off64_t lseek64(int __fd, off64_t __offset, int __whence);
 
-#if defined(__USE_FILE_OFFSET64) && __ANDROID_API__ >= __ANDROID_API_L__
+#if defined(__USE_FILE_OFFSET64)
 int truncate(const char* __path, off_t __length) __RENAME(truncate64) __INTRODUCED_IN(21);
 ssize_t pread(int __fd, void* __buf, size_t __count, off_t __offset)
   __overloadable __RENAME(pread64) __INTRODUCED_IN(12);