libssh2_sftp.h: Changed type of LIBSSH2_FX_* constants to unsigned long, fixes #474

File:
libssh2_sftp.h 

Notes:
Error constants `LIBSSH2_FX_*` are only returned by `libssh2_sftp_last_error()` which returns `unsigned long`.
Therefore these constants should be defined as unsigned long literals, instead of int literals.

Credit:
Dr. Koutheir Attouchi

include/libssh2_sftp.h

@@ -189,30 +189,30 @@ struct _LIBSSH2_SFTP_STATVFS {
 #define LIBSSH2_FXF_EXCL                        0x00000020
 
 /* SFTP Status Codes (returned by libssh2_sftp_last_error() ) */
-#define LIBSSH2_FX_OK                       0
+#define LIBSSH2_FX_OK                       0UL
-#define LIBSSH2_FX_EOF                      1
+#define LIBSSH2_FX_EOF                      1UL
-#define LIBSSH2_FX_NO_SUCH_FILE             2
+#define LIBSSH2_FX_NO_SUCH_FILE             2UL
-#define LIBSSH2_FX_PERMISSION_DENIED        3
+#define LIBSSH2_FX_PERMISSION_DENIED        3UL
-#define LIBSSH2_FX_FAILURE                  4
+#define LIBSSH2_FX_FAILURE                  4UL
-#define LIBSSH2_FX_BAD_MESSAGE              5
+#define LIBSSH2_FX_BAD_MESSAGE              5UL
-#define LIBSSH2_FX_NO_CONNECTION            6
+#define LIBSSH2_FX_NO_CONNECTION            6UL
-#define LIBSSH2_FX_CONNECTION_LOST          7
+#define LIBSSH2_FX_CONNECTION_LOST          7UL
-#define LIBSSH2_FX_OP_UNSUPPORTED           8
+#define LIBSSH2_FX_OP_UNSUPPORTED           8UL
-#define LIBSSH2_FX_INVALID_HANDLE           9
+#define LIBSSH2_FX_INVALID_HANDLE           9UL
-#define LIBSSH2_FX_NO_SUCH_PATH             10
+#define LIBSSH2_FX_NO_SUCH_PATH             10UL
-#define LIBSSH2_FX_FILE_ALREADY_EXISTS      11
+#define LIBSSH2_FX_FILE_ALREADY_EXISTS      11UL
-#define LIBSSH2_FX_WRITE_PROTECT            12
+#define LIBSSH2_FX_WRITE_PROTECT            12UL
-#define LIBSSH2_FX_NO_MEDIA                 13
+#define LIBSSH2_FX_NO_MEDIA                 13UL
-#define LIBSSH2_FX_NO_SPACE_ON_FILESYSTEM   14
+#define LIBSSH2_FX_NO_SPACE_ON_FILESYSTEM   14UL
-#define LIBSSH2_FX_QUOTA_EXCEEDED           15
+#define LIBSSH2_FX_QUOTA_EXCEEDED           15UL
-#define LIBSSH2_FX_UNKNOWN_PRINCIPLE        16 /* Initial mis-spelling */
+#define LIBSSH2_FX_UNKNOWN_PRINCIPLE        16UL /* Initial mis-spelling */
-#define LIBSSH2_FX_UNKNOWN_PRINCIPAL        16
+#define LIBSSH2_FX_UNKNOWN_PRINCIPAL        16UL
-#define LIBSSH2_FX_LOCK_CONFlICT            17 /* Initial mis-spelling */
+#define LIBSSH2_FX_LOCK_CONFlICT            17UL /* Initial mis-spelling */
-#define LIBSSH2_FX_LOCK_CONFLICT            17
+#define LIBSSH2_FX_LOCK_CONFLICT            17UL
-#define LIBSSH2_FX_DIR_NOT_EMPTY            18
+#define LIBSSH2_FX_DIR_NOT_EMPTY            18UL
-#define LIBSSH2_FX_NOT_A_DIRECTORY          19
+#define LIBSSH2_FX_NOT_A_DIRECTORY          19UL
-#define LIBSSH2_FX_INVALID_FILENAME         20
+#define LIBSSH2_FX_INVALID_FILENAME         20UL
-#define LIBSSH2_FX_LINK_LOOP                21
+#define LIBSSH2_FX_LINK_LOOP                21UL
 
 /* Returned by any function that would block during a read/write operation */
 #define LIBSSH2SFTP_EAGAIN LIBSSH2_ERROR_EAGAIN