remove system.getFileSize again, breaks windows builds and I don't want more stuff that's a pain to support in a platform independent manner

lib/system.nim

@@ -2895,9 +2895,6 @@ when not defined(JS): #and not defined(nimscript):
     proc getFileSize*(f: File): int64 {.tags: [ReadIOEffect], benign.}
       ## retrieves the file size (in bytes) of `f`.
 
-    proc setFileSize*(f: File, size: int64) {.tags: [ReadIOEffect], benign.}
-      ## changes the size of file `f` (in bytes).
-
     proc readBytes*(f: File, a: var openArray[int8|uint8], start, len: Natural): int {.
       tags: [ReadIOEffect], benign.}
       ## reads `len` bytes into the buffer `a` starting at ``a[start]``. Returns

lib/system/sysio.nim

@@ -52,8 +52,6 @@ proc c_ferror(f: File): cint {.
   importc: "ferror", header: "<stdio.h>", tags: [].}
 proc c_setvbuf(f: File, buf: pointer, mode: cint, size: csize): cint {.
   importc: "setvbuf", header: "<stdio.h>", tags: [].}
-proc c_ftruncate(f: FileHandle, len: clong): cint {.
-  importc: "ftruncate", header: "<unistd.h>".}
 
 proc raiseEIO(msg: string) {.noinline, noreturn.} =
   sysFatal(IOError, msg)
@@ -375,11 +373,6 @@ proc getFileSize(f: File): int64 =
   result = getFilePos(f)
   setFilePos(f, oldPos)
 
-proc setFileSize(f: File, size: int64) =
-  ## Set a file length.
-  if c_ftruncate(getFileHandle f, size.clong) == -1:
-    raiseEIO("cannot truncate file")
-
 proc readFile(filename: string): TaintedString =
   var f: File
   if open(f, filename):