changed integer promotion rules; breaks bootstrapping and lots of code

lib/system/ansi_c.nim

@@ -71,7 +71,8 @@ proc c_fopen(filename, mode: cstring): C_TextFileStar {.
   importc: "fopen", nodecl.}
 proc c_fclose(f: C_TextFileStar) {.importc: "fclose", nodecl.}
 
-proc c_sprintf(buf, frmt: CString) {.nodecl, importc: "sprintf", varargs.}
+proc c_sprintf(buf, frmt: CString) {.nodecl, importc: "sprintf", varargs,
+                                     noSideEffect.}
   # we use it only in a way that cannot lead to security issues
 
 proc c_fread(buf: Pointer, size, n: int, f: C_BinaryFileStar): int {.

lib/system/repr.nim

@@ -20,6 +20,11 @@ proc reprPointer(x: pointer): string {.compilerproc.} =
   c_sprintf(buf, "%p", x)
   return $buf
 
+proc `$`(x: uint64): string =
+  var buf: array [0..59, char]
+  c_sprintf(buf, "%llu", x)
+  return $buf
+
 proc reprStrAux(result: var string, s: string) =
   if cast[pointer](s) == nil:
     add result, "nil"
@@ -67,7 +72,7 @@ proc reprEnum(e: int, typ: PNimType): string {.compilerRtl.} =
   result = $e & " (invalid data!)"
 
 type
-  pbyteArray = ptr array[0.. 0xffff, byte]
+  pbyteArray = ptr array[0.. 0xffff, int8]
 
 proc addSetElem(result: var string, elem: int, typ: PNimType) =
   case typ.kind

lib/system/sysio.nim

@@ -222,17 +222,17 @@ proc fwrite(buf: Pointer, size, n: int, f: TFile): int {.
 proc readBuffer(f: TFile, buffer: pointer, len: int): int =
   result = fread(buffer, 1, len, f)
 
-proc ReadBytes(f: TFile, a: var openarray[byte], start, len: int): int =
+proc ReadBytes(f: TFile, a: var openarray[int8], start, len: int): int =
   result = readBuffer(f, addr(a[start]), len)
 
 proc ReadChars(f: TFile, a: var openarray[char], start, len: int): int =
   result = readBuffer(f, addr(a[start]), len)
 
-proc writeBytes(f: TFile, a: openarray[byte], start, len: int): int =
-  var x = cast[ptr array[0..1000_000_000, byte]](a)
+proc writeBytes(f: TFile, a: openarray[int8], start, len: int): int =
+  var x = cast[ptr array[0..1000_000_000, int8]](a)
   result = writeBuffer(f, addr(x[start]), len)
 proc writeChars(f: TFile, a: openarray[char], start, len: int): int =
-  var x = cast[ptr array[0..1000_000_000, byte]](a)
+  var x = cast[ptr array[0..1000_000_000, int8]](a)
   result = writeBuffer(f, addr(x[start]), len)
 proc writeBuffer(f: TFile, buffer: pointer, len: int): int =
   result = fwrite(buffer, 1, len, f)