Misc fixes

Util_getToken: fix stack overflow

md5_append will overflow buf, cause STRLEN - 1 is given as length

introduced by 240b2e4b7785ddc3b93d7668d999def7cd742a3c

md5_process: whitelist intentional unsigned integer overflow

creates noise when using unsigned behavior sanitizer

file_checkState: change permmask type to mode_t

src/file.c:174:36: runtime error: implicit conversion from type 'int' of value -449 (32-bit, signed) to type 'unsigned int' changed the value to 4294966847 (32-bit, unsigned)

Engine_cleanup: avoid unlink(NULL) on shutdown

Engine_cleanup() might be called twice, the second time with Run.httpd.socket.unix.path already freed

src/http/engine.c:530:24: runtime error: null pointer passed as argument 1, which is declared to never be null /usr/include/unistd.h:825:48: note: nonnull attribute specified here

parser: add missing semicolon

fix implicit conversion

found by clang

src/alert.c:194:95: warning: implicit conversion from enumeration type 'boolean_t' to different enumeration type 'Ssl_Flags' [-Wenum-conversion] mta->socket = Socket_new(mta->host, mta->port, Socket_Tcp, Socket_Ip, false, Run.mailserver_timeout); ~~ ^~~~~ 1 warning generated.

fix clang Wmissing-prototypes warnings