Fix warnings

This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.

tool/plinko/lib/read.c

@@ -98,8 +98,7 @@ dontinstrument int ReadChar(int fd) {
 }
 
 static int ReadListItem(int fd, int closer, int f(int)) {
-  int i, n, x, y;
-  dword t;
+  int x, y;
   if ((x = f(fd)) > 0) {
     if (Get(x) == MAKE(closer, TERM)) return -0;
     if (Get(x) == MAKE(L'.', TERM)) {
@@ -123,7 +122,7 @@ static int ReadList(int fd, int closer) {
 
 static int TokenizeInteger(int fd, int b) {
   dword a;
-  int c, i, x, y;
+  int c, i;
   for (i = a = 0;; ++i) {
     if ((c = GetDiglet(ToUpper(dx))) != -1 && c < b) {
       a = (a * b) + c;
@@ -146,7 +145,7 @@ static void ConsumeComment(int fd) {
 }
 
 static int ReadAtomRest(int fd, int x) {
-  int y, t, u;
+  int y;
   ax = y = TERM;
   if (x == L'\\') x = ReadChar(fd);
   if (!IsSpace(dx) && !IsParen(dx) && !IsMathAlnum(x) && !IsMathAlnum(dx)) {
@@ -194,7 +193,7 @@ static int TokenizeComplicated(int fd) {
 }
 
 static int Read2(int fd) {
-  int r, f, t, l;
+  int r, l;
   while (IsSpace((l = dx))) ReadChar(fd);
   switch (dx) {
     case L'#':