Fix sign bugs.

PR: 621

crypto/asn1/a_strex.c

@@ -279,7 +279,7 @@ static int do_dump(unsigned long lflags, char_io *io_ch, void *arg, ASN1_STRING
  * otherwise it is the number of bytes per character
  */
 
-const static char tag2nbyte[] = {
+const static signed char tag2nbyte[] = {
 	-1, -1, -1, -1, -1,	/* 0-4 */
 	-1, -1, -1, -1, -1,	/* 5-9 */
 	-1, -1, 0, -1,		/* 10-13 */

crypto/bio/b_print.c

@@ -836,5 +836,5 @@ int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args)
 		 * had the buffer been large enough.) */
 		return -1;
 	else
-		return (retlen <= INT_MAX) ? retlen : -1;
+		return (retlen <= INT_MAX) ? (int)retlen : -1;
 	}

crypto/bn/bn_mul.c

@@ -549,7 +549,7 @@ void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,
 	     int tna, int tnb, BN_ULONG *t)
 	{
 	int i,j,n2=n*2;
-	unsigned int c1,c2,neg,zero;
+	int c1,c2,neg,zero;
 	BN_ULONG ln,lo,*p;
 
 # ifdef BN_COUNT