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.

dsp/core/c121.h

@@ -5,7 +5,7 @@ COSMOPOLITAN_C_START_
 
 __funline unsigned char C121(unsigned char al, unsigned char bl,
                              unsigned char cl) {
-  unsigned short ax, bx;
+  unsigned short ax;
   ax = al;
   ax += bl;
   ax += bl;

dsp/core/c121s.h

@@ -3,7 +3,7 @@
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 
 __funline signed char C121S(signed char al, signed char bl, signed char cl) {
-  short ax, bx;
+  short ax;
   ax = al;
   ax += bl;
   ax += bl;

dsp/core/sad16x8n.c

@@ -31,13 +31,14 @@
  * @param y needs to be 16-byte aligned
  */
 void sad16x8n(size_t n, short x[n][8], const short y[n][8]) {
-  size_t i, j;
+  size_t i;
   for (i = 0; i < n; ++i) {
 #ifdef __x86_64__
     *(__m128i *)x[i] = _mm_adds_epi16(*(__m128i *)x[i], *(__m128i *)y[i]);
 #elif defined(__aarch64__)
     *(int16x4_t *)x[i] = vqadd_s16(*(int16x4_t *)x[i], *(int16x4_t *)y[i]);
 #else
+    size_t j;
     for (j = 0; j < 8; ++j) {
       x[i][j] = MIN(MAX(x[i][j] + y[i][j], INT16_MIN), INT16_MAX);
     }

dsp/mpeg/idct.c

@@ -41,7 +41,7 @@ asm(".include \"libc/disclaimer.inc\"");
  * @note discovered by Nasir Ahmed
  */
 void plm_video_idct(int block[8][8]) {
-  int i, j, t1, t2, m0;
+  int i, t1, t2, m0;
   int b1, b3, b4, b6, b7;
   int y3, y4, y5, y6, y7;
   int x0, x1, x2, x3, x4;

dsp/mpeg/mpeg1.c

@@ -1105,12 +1105,12 @@ plm_video_t *plm_video_create_with_buffer(plm_buffer_t *buffer,
 
 static textstartup void plm_video_init(void) {
   PLM_VIDEO_MACROBLOCK_TYPE[0] = NULL;
-  PLM_VIDEO_MACROBLOCK_TYPE[1] = PLM_VIDEO_MACROBLOCK_TYPE_INTRA;
-  PLM_VIDEO_MACROBLOCK_TYPE[2] = PLM_VIDEO_MACROBLOCK_TYPE_PREDICTIVE,
-  PLM_VIDEO_MACROBLOCK_TYPE[3] = PLM_VIDEO_MACROBLOCK_TYPE_B;
-  PLM_VIDEO_DCT_SIZE[0] = PLM_VIDEO_DCT_SIZE_LUMINANCE;
-  PLM_VIDEO_DCT_SIZE[1] = PLM_VIDEO_DCT_SIZE_CHROMINANCE;
-  PLM_VIDEO_DCT_SIZE[2] = PLM_VIDEO_DCT_SIZE_CHROMINANCE;
+  PLM_VIDEO_MACROBLOCK_TYPE[1] = (void *)PLM_VIDEO_MACROBLOCK_TYPE_INTRA;
+  PLM_VIDEO_MACROBLOCK_TYPE[2] = (void *)PLM_VIDEO_MACROBLOCK_TYPE_PREDICTIVE;
+  PLM_VIDEO_MACROBLOCK_TYPE[3] = (void *)PLM_VIDEO_MACROBLOCK_TYPE_B;
+  PLM_VIDEO_DCT_SIZE[0] = (void *)PLM_VIDEO_DCT_SIZE_LUMINANCE;
+  PLM_VIDEO_DCT_SIZE[1] = (void *)PLM_VIDEO_DCT_SIZE_CHROMINANCE;
+  PLM_VIDEO_DCT_SIZE[2] = (void *)PLM_VIDEO_DCT_SIZE_CHROMINANCE;
 }
 
 const void *const plm_video_init_ctor[] initarray = {plm_video_init};

dsp/scale/cdecimate2xuint8x8.c

@@ -55,10 +55,10 @@ void *cDecimate2xUint8x8(unsigned long n, unsigned char A[n],
                             K[4], K[5], K[4], K[5], K[4], K[5], K[4], K[5]};
   signed char kMadd4[16] = {K[6], K[7], K[6], K[7], K[6], K[7], K[6], K[7],
                             K[6], K[7], K[6], K[7], K[6], K[7], K[6], K[7]};
-  unsigned char in1[16], in2[16], in3[16], in4[32];
   unsigned char bv0[16], bv1[16], bv2[16], bv3[16];
+  unsigned char in1[16], in2[16], in3[16];
   short wv0[8], wv1[8], wv2[8], wv3[8];
-  unsigned long i, j, v, w, o;
+  unsigned long i, j, w;
   if (n >= STRIDE) {
     i = 0;
     w = (n + RATIO / 2) / RATIO;

dsp/scale/gyarados.c

@@ -82,7 +82,6 @@ static bool IsNormalized(int n, double A[n]) {
 }
 
 void FreeSamplingSolution(struct SamplingSolution *ss) {
-  long i;
   if (ss) {
     free(ss->indices);
     free(ss->weights);
@@ -93,7 +92,7 @@ void FreeSamplingSolution(struct SamplingSolution *ss) {
 struct SamplingSolution *ComputeSamplingSolution(long dn, long sn, double dar,
                                                  double off, double par) {
   double *fweights;
-  double sum, hw, w, x, f;
+  double sum, hw, x, f;
   short *weights, *indices;
   struct SamplingSolution *res;
   long j, i, k, n, min, max, s, N[6];
@@ -151,8 +150,8 @@ static void GyaradosImpl(long dyw, long dxw, int dst[dyw][dxw], long syw,
                          const short fyi[dyn][yfn], const short fyw[dyn][yfn],
                          const short fxi[dxn][xfn], const short fxw[dxn][xfn],
                          bool sharpen) {
-  long i, j;
-  int eax, dy, dx, sy, sx;
+  long i;
+  int eax, dy, dx, sx;
   for (sx = 0; sx < sxn; ++sx) {
     for (dy = 0; dy < dyn; ++dy) {
       for (eax = i = 0; i < yfn; ++i) {

dsp/tty/rgb2ansi.c

@@ -98,8 +98,8 @@ static int uncube(int x) {
 }
 
 static textstartup void rgb2ansi_init(void) {
-  uint8_t c, y;
-  uint32_t i, j;
+  uint8_t c;
+  uint32_t i;
   memcpy(g_ansi2rgb_, &kCgaPalette, sizeof(kCgaPalette));
   for (i = 16; i < 232; ++i) {
     g_ansi2rgb_[i].r = kXtermCube[((i - 020) / 044) % 06];

dsp/tty/ttyraster.c

@@ -609,7 +609,7 @@ static struct Pick PickBlockUnicodeAnsi(struct TtyRgb tl, struct TtyRgb tr,
   struct TtyRgb tr2 = GetQuant(tr);
   struct TtyRgb bl2 = GetQuant(bl);
   struct TtyRgb br2 = GetQuant(br);
-  unsigned i, p1, p2;
+  unsigned p1, p2;
   uint16_t picks1[96] forcealign(32);
   uint16_t picks2[32] forcealign(32);
   memset(picks1, 0x79, sizeof(picks1));
@@ -646,7 +646,7 @@ static struct Pick PickBlockCp437Ansi(struct TtyRgb tl, struct TtyRgb tr,
   struct TtyRgb tr2 = GetQuant(tr);
   struct TtyRgb bl2 = GetQuant(bl);
   struct TtyRgb br2 = GetQuant(br);
-  unsigned i, p1, p2;
+  unsigned p1, p2;
   uint16_t picks1[32] forcealign(32);
   uint16_t picks2[32] forcealign(32);
   memset(picks1, 0x79, sizeof(picks1));
@@ -660,7 +660,6 @@ static struct Pick PickBlockCp437Ansi(struct TtyRgb tl, struct TtyRgb tr,
 
 static struct Pick PickBlockCp437True(struct TtyRgb tl, struct TtyRgb tr,
                                       struct TtyRgb bl, struct TtyRgb br) {
-  unsigned i;
   uint16_t picks[32] forcealign(32);
   memset(picks, 0x79, sizeof(picks));
   PickCp437(picks, tl, tr, bl, br, tl, tr, bl, br);

dsp/tty/write.c

@@ -38,8 +38,8 @@
  * @return 0 on success, or -1 w/ errno
  */
 ssize_t ttywrite(int fd, const void *data, size_t size) {
-  char *p;
   ssize_t rc;
+  const char *p;
   size_t wrote, n;
   p = data;
   n = size;