Error codes are uint32_t, not unsigned long.

Fix a few remnants of them being unsigned long. Also rename extremely unhelpful
variable names in SSL_get_error. i is now ret_code to match the header.

Change-Id: Ic31d6626bfe09c9e21c03691dfc716c5573833ea
Reviewed-on: https://boringssl-review.googlesource.com/3881
Reviewed-by: Adam Langley <agl@google.com>

crypto/asn1/a_d2i_fp.c

@@ -194,7 +194,7 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
 			len-off);
 		if (c.inf & 0x80)
 			{
-			unsigned long e;
+			uint32_t e;
 
 			e=ERR_GET_REASON(ERR_peek_error());
 			if (e != ASN1_R_TOO_LONG)

crypto/bn/bn_test.c

@@ -968,7 +968,7 @@ int test_mod_mul(BIO *bp, BN_CTX *ctx) {
       a->neg = rand_neg();
       b->neg = rand_neg();
       if (!BN_mod_mul(e, a, b, c, ctx)) {
-        unsigned long l;
+        uint32_t l;
 
         while ((l = ERR_get_error())) {
           fprintf(stderr, "ERROR:%s\n", ERR_error_string(l, NULL));

ssl/ssl_lib.c

@@ -2205,26 +2205,26 @@ void ssl_update_cache(SSL *s, int mode) {
   }
 }
 
-int SSL_get_error(const SSL *s, int i) {
+int SSL_get_error(const SSL *s, int ret_code) {
   int reason;
-  unsigned long l;
+  uint32_t err;
   BIO *bio;
 
-  if (i > 0) {
+  if (ret_code > 0) {
     return SSL_ERROR_NONE;
   }
 
   /* Make things return SSL_ERROR_SYSCALL when doing SSL_do_handshake etc,
    * where we do encode the error */
-  l = ERR_peek_error();
-  if (l != 0) {
-    if (ERR_GET_LIB(l) == ERR_LIB_SYS) {
+  err = ERR_peek_error();
+  if (err != 0) {
+    if (ERR_GET_LIB(err) == ERR_LIB_SYS) {
       return SSL_ERROR_SYSCALL;
     }
     return SSL_ERROR_SSL;
   }
 
-  if (i == 0) {
+  if (ret_code == 0) {
     if ((s->shutdown & SSL_RECEIVED_SHUTDOWN) &&
         (s->s3->warn_alert == SSL_AD_CLOSE_NOTIFY)) {
       /* The socket was cleanly shut down with a close_notify. */