Remove code needed for supporting old VS versions.

[abidh]

Summary

This code was probably needed to support VS2013 and is not needed now. I have built it with VS and mingw. Ok to remove it?

[abidh]

Accepted on email.

include/lldb/Host/windows/PosixApi.h

 #define S_IFDIR _S_IFDIR
 
 #ifndef S_ISDIR
 #define S_ISDIR(mode) (((mode)&S_IFMT) == S_IFDIR)
 #endif
 
 #endif // _MSC_VER
 
-// MSVC 2015 and higher have timespec.  Otherwise we need to define it
-// ourselves.
-#if !defined(_MSC_VER) || _MSC_VER < 1900
-struct timespec {
-  time_t tv_sec;
-  long tv_nsec;
-};
-#endif
-
 // Various useful posix functions that are not present in Windows.  We provide
 // custom implementations.
 int vasprintf(char **ret, const char *fmt, va_list ap);
 char *strcasestr(const char *s, const char *find);
 char *realpath(const char *name, char *resolved);
 
 int usleep(uint32_t useconds);
 char *getcwd(char *path, int max);

 
 inline int unlockpt(int fd) { LLVM_BUILTIN_UNREACHABLE; }
 inline int grantpt(int fd) { LLVM_BUILTIN_UNREACHABLE; }
 inline char *ptsname(int fd) { LLVM_BUILTIN_UNREACHABLE; }
 
 inline pid_t fork(void) { LLVM_BUILTIN_UNREACHABLE; }
 inline pid_t setsid(void) { LLVM_BUILTIN_UNREACHABLE; }
 
-// vsnprintf and snprintf are provided in MSVC 2015 and higher.
-#if _MSC_VER < 1900
-namespace lldb_private {
-int vsnprintf(char *buffer, size_t count, const char *format, va_list argptr);
-}
-
-// inline to avoid linkage conflicts
-int inline snprintf(char *buffer, size_t count, const char *format, ...) {
-  va_list argptr;
-  va_start(argptr, format);
-  int r = lldb_private::vsnprintf(buffer, count, format, argptr);
-  va_end(argptr);
-  return r;
-}
-#endif
-
 #endif