checksrc: warn on empty line before open brace

... and fix a few occurances

Closes #6088

lib/checksrc.pl

@@ -85,6 +85,7 @@ my %warnings = (
     'DOBRACE'          => 'A single space between do and open brace',
     'BRACEWHILE'       => 'A single space between open brace and while',
     'EXCLAMATIONSPACE' => 'Whitespace after exclamation mark in expression',
+    'EMPTYLINEBRACE'   => 'Empty line before the open brace',
     );
 
 sub readskiplist {
@@ -594,6 +595,11 @@ sub scanfile {
             checkwarn("PARENBRACE",
                       $line, length($1)+1, $file, $l, "missing space after close paren");
         }
+        # check for "^{" with an empty line before it
+        if(($l =~ /^\{/) && ($prevl =~ /^[ \t]*\z/)) {
+            checkwarn("EMPTYLINEBRACE",
+                      $line, 0, $file, $l, "empty line before open brace");
+        }
 
         # check for space before the semicolon last in a line
         if($l =~ /^(.*[^ ].*) ;$/) {

lib/ftp.c

@@ -901,7 +901,6 @@ typedef enum {
 
 static CURLcode ftp_state_use_port(struct connectdata *conn,
                                    ftpport fcmd) /* start with this */
-
 {
   CURLcode result = CURLE_OK;
   struct ftp_conn *ftpc = &conn->proto.ftpc;

lib/multi.c

@@ -3158,7 +3158,6 @@ CURLMcode curl_multi_socket_action(struct Curl_multi *multi, curl_socket_t s,
 }
 
 CURLMcode curl_multi_socket_all(struct Curl_multi *multi, int *running_handles)
-
 {
   CURLMcode result;
   if(multi->in_callback)

lib/vauth/ntlm.c

@@ -497,7 +497,6 @@ CURLcode Curl_auth_create_ntlm_type3_message(struct Curl_easy *data,
                                              const char *passwdp,
                                              struct ntlmdata *ntlm,
                                              char **outptr, size_t *outlen)
-
 {
   /* NTLM type-3 message structure:
 

lib/vtls/openssl.c

@@ -3453,7 +3453,6 @@ typedef int numcert_t;
 
 static CURLcode get_cert_chain(struct connectdata *conn,
                                struct ssl_connect_data *connssl)
-
 {
   CURLcode result;
   STACK_OF(X509) *sk;

tests/unit/unit1604.c

@@ -82,7 +82,6 @@ struct data {
 };
 
 UNITTEST_START
-
 { /* START sanitize_file_name */
   struct data data[] = {
     { "", 0,
@@ -349,7 +348,6 @@ UNITTEST_START
 
 #else
 UNITTEST_START
-
 {
   fprintf(stderr, "Skipped test not for this platform\n");
 }