Merge pull request #4444 from proller/fix15

 Build fixes (freebsd)

cmake/find_rdkafka.cmake

-if (NOT ARCH_ARM AND NOT ARCH_32 AND NOT APPLE)
+# Freebsd: contrib/cppkafka/include/cppkafka/detail/endianness.h:53:23: error: 'betoh16' was not declared in this scope
+if (NOT ARCH_ARM AND NOT ARCH_32 AND NOT APPLE AND NOT OS_FREEBSD)
     option (ENABLE_RDKAFKA "Enable kafka" ON)
 endif ()
 

cmake/find_xxhash.cmake

 # Freebsd: TODO: use system devel/xxhash. now error: undefined reference to `XXH32'
-if (LZ4_INCLUDE_DIR AND NOT OS_FREEBSD)
+if (LZ4_INCLUDE_DIR)
     if (NOT EXISTS "${LZ4_INCLUDE_DIR}/xxhash.h")
         message (WARNING "LZ4 library does not have XXHash. Support for XXHash will be disabled.")
         set (USE_XXHASH 0)
@@ -8,4 +8,8 @@ if (LZ4_INCLUDE_DIR AND NOT OS_FREEBSD)
     endif ()
 endif ()
 
+if (OS_FREEBSD AND NOT USE_INTERNAL_LZ4_LIBRARY)
+    set (USE_XXHASH 0)
+endif ()
+
 message (STATUS "Using xxhash=${USE_XXHASH}")