cmake: remove unconditional -Wno-deprecated-declaration on APPLE

After taking into consideration the following, I think this should be
removed :

- OpenSSL isn't the default on Apple platforms
- you have to jump through hoops to get CMake to use OpenSSL on macOS
(headers aren't in `/usr/include`, so you have to provide `-DOPENSSL_*`
overrides)
- users are likely (as getting anywhere near the installed 0.9.8 version
is insanity IMHO) to package a "modern" version, which wouldn't be
marked as deprecated

Author: tiennou

CMakeLists.txt

@@ -235,9 +235,6 @@ ELSE ()
 	ENABLE_WARNINGS(int-conversion)
 	DISABLE_WARNINGS(documentation-deprecated-sync)
 
-	IF (APPLE) # Apple deprecated OpenSSL
-	    DISABLE_WARNINGS(deprecated-declarations)
-	ENDIF()
 
 	IF (PROFILE)
 		SET(CMAKE_C_FLAGS "-pg ${CMAKE_C_FLAGS}")