ttyd: fix compilation without deprecated OpenSSL APIs

Removed CMAKE_INSTALL as there's no need for InstallDev.

Added PKG_BUILD_PARALLEL for faster compilation.

Small cleanups.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

utils/ttyd/patches/200-openssl.patch

@@ -0,0 +1,9 @@
+--- a/src/http.c
++++ b/src/http.c
+@@ -1,5 +1,6 @@
+ #include <string.h>
+ #include <libwebsockets.h>
++#include <openssl/ssl.h>
+ 
+ #include "server.h"
+ #include "html.h"