obs-outputs: Fix build with older mbedtls versions

Compilation with older versions of mbedtls was broken by
https://github.com/obsproject/obs-studio/pull/2304, unfortunately the
older version is still present in Ubuntu 16 LTS.

plugins/obs-outputs/librtmp/rtmp.c

@@ -2711,9 +2711,16 @@ b64enc(const unsigned char *input, int length, char *output, int maxsize)
 
 #if defined(USE_MBEDTLS)
 typedef	mbedtls_md5_context MD5_CTX;
+
+#if MBEDTLS_VERSION_NUMBER >= 0x02040000
 #define MD5_Init(ctx)	mbedtls_md5_init(ctx); mbedtls_md5_starts_ret(ctx)
 #define MD5_Update(ctx,data,len)	mbedtls_md5_update_ret(ctx,(unsigned char *)data,len)
 #define MD5_Final(dig,ctx)	mbedtls_md5_finish_ret(ctx,dig); mbedtls_md5_free(ctx)
+#else
+#define MD5_Init(ctx)	mbedtls_md5_init(ctx); mbedtls_md5_starts(ctx)
+#define MD5_Update(ctx,data,len)	mbedtls_md5_update(ctx,(unsigned char *)data,len)
+#define MD5_Final(dig,ctx)	mbedtls_md5_finish(ctx,dig); mbedtls_md5_free(ctx)
+#endif
 
 #elif defined(USE_POLARSSL)
 #define MD5_CTX	md5_context

plugins/obs-outputs/librtmp/rtmp.h

@@ -52,7 +52,13 @@
 #ifdef CRYPTO
 #if defined(USE_MBEDTLS)
 #include <mbedtls/version.h>
+
+#if MBEDTLS_VERSION_NUMBER >= 0x02040000
 #include <mbedtls/net_sockets.h>
+#else
+#include <mbedtls/net.h>
+#endif
+
 #include <mbedtls/ssl.h>
 #include <mbedtls/ctr_drbg.h>
 #include <mbedtls/entropy.h>