Fix Cygwin compilation:

- Fix various incompatibilities and differences between Linux and Cygwin builds
- Make usrsctp an optional dependency
- Fix building without SSL
- Add new secure random bytes function, use it for websockets
- Switch to libsrtp2 v2.6.0 (currently latest release)
- Add patch that makes latest libsrtp2 build in latest Cygwin
- Add patch that makes srt build in latest Cygwin
- Correctly allow linking libsrtp2 and srt to local mbedtls version

src/input/input.cpp

@@ -1604,6 +1604,7 @@ namespace Mist{
         if (connectedUsers || isAlwaysOn()){activityCounter = Util::bootSecs();}
         if (thisTime >= lastBuffered){
           if (sourceIdx != idx){
+#ifdef SSL
             if (encryption.find(":") != std::string::npos || M.getEncryption(idx).find(":") != std::string::npos){
               if (encryption == ""){
                 encryption = M.getEncryption(idx);
@@ -1622,8 +1623,11 @@ namespace Mist{
                 thisPacket = encPacket;
               }
             }else{
+#endif
               thisPacket = DTSC::Packet(thisPacket, idx);
+#ifdef SSL
             }
+#endif
           }
           //Sanity check: are we matching the key's data size?
           if (thisPacket.getFlag("keyframe")){

src/input/input.h

@@ -5,13 +5,16 @@
 #include <mist/config.h>
 #include <mist/defines.h>
 #include <mist/dtsc.h>
-#include <mist/encryption.h>
 #include <mist/json.h>
 #include <mist/shared_memory.h>
 #include <mist/timing.h>
 #include <mist/url.h>
 #include <set>
 
+#ifdef SSL
+#include <mist/encryption.h>
+#endif
+
 #include "../io.h"
 
 namespace Mist{
@@ -110,7 +113,9 @@ namespace Mist{
     Comms::Users users;
     size_t connectedUsers;
 
+#ifdef SSL
     Encryption::AES aesCipher;
+#endif
 
     IPC::sharedPage streamStatus;
 

src/input/input_hls.cpp

@@ -1,5 +1,7 @@
 #include "input_hls.h"
+#ifdef SSL
 #include "mbedtls/aes.h"
+#endif
 #include <algorithm>
 #include <cerrno>
 #include <cstdio>

src/input/input_hls.h

@@ -67,7 +67,9 @@ namespace Mist{
     Util::ResizeablePointer * currBuf;
     size_t encOffset;
     unsigned char tmpIvec[16];
+#ifdef SSL
     mbedtls_aes_context aes;
+#endif
     bool isOpen;
   };