Implement some of the missing LFS64 support.

This gives us:

* <dirent.h>
  struct dirent64
  readdir64, readdir64_r, alphasort64, scandir64

* <fcntl.h>
  creat64, openat64, open64.

* <sys/stat.h>
  struct stat64
  fstat64, fstatat64, lstat64, stat64.

* <sys/statvfs.h>
  struct statvfs64
  statvfs64, fstatvfs64.

* <sys/vfs.h>
  struct statfs64
  statfs64, fstatfs64.

This also removes some of the incorrect #define hacks we've had in the
past (for stat64, for example, which we promised to clean up way back
in bug 8472078).

Bug: 11865851
Bug: 8472078
Change-Id: Ia46443521918519f2dfa64d4621027dfd13ac566
diff --git a/libc/bionic/legacy_32_bit_support.cpp b/libc/bionic/legacy_32_bit_support.cpp
index 411daa0..73f77be 100644
--- a/libc/bionic/legacy_32_bit_support.cpp
+++ b/libc/bionic/legacy_32_bit_support.cpp
@@ -59,11 +59,13 @@
 int fstatfs(int fd, struct statfs* stat) {
   return __fstatfs64(fd, sizeof(*stat), stat);
 }
+__strong_alias(fstatfs64, fstatfs);
 
 // For statfs we need to add the extra argument giving the kernel the size of the buffer.
 int statfs(const char* path, struct statfs* stat) {
   return __statfs64(path, sizeof(*stat), stat);
 }
+__strong_alias(statfs64, statfs);
 
 // For lseek64 we need to use the llseek system call which splits the off64_t in two and
 // returns the off64_t result via a pointer because 32-bit kernels can't return 64-bit results.