Add lz4 to the build

.gitmodules

@@ -16,3 +16,6 @@
 [submodule "main/src/main/cpp/asio"]
 	path = main/src/main/cpp/asio
 	url = ../../chriskohlhoff/asio/
+[submodule "main/src/main/cpp/lz4"]
+	path = main/src/main/cpp/lz4
+	url = ../../lz4/lz4.git

main/src/main/cpp/CMakeLists.txt

@@ -16,6 +16,7 @@ OPTION(ENABLE_TESTING ""  OFF)
 #add_subdirectory(lzo)
 include(tools.cmake)
 include(lzo.cmake)
+include(lz4.cmake)
 include(openssl.cmake)
 
 # Super hacky way to determine flavour
@@ -61,13 +62,14 @@ if (NOT ${CMAKE_LIBRARY_OUTPUT_DIRECTORY} MATCHES "build/intermediates/cmake/.*n
     target_compile_definitions(ovpn3 PRIVATE
       -DHAVE_CONFIG_H
       -DHAVE_LZO
+      -DHAVE_LZ4
       -DASIO_STANDALONE
       -DUSE_ASIO
       -DUSE_MBEDTLS
       -DGIT_VERSION_STRING=\"${OPENVPN3_GIT}\"
       -DNO_ROUTE_EXCLUDE_EMULATION
       )
-    target_link_libraries(ovpn3 mbedtls mbedx509 mbedcrypto lzo)
+    target_link_libraries(ovpn3 mbedtls mbedx509 mbedcrypto lzo lz4)
 else()
     message ("Not budiling OpenVPN for output dir ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}")
 endif()

main/src/main/cpp/lz4

@@ -0,0 +1 @@
+Subproject commit cadf5cd5f9289a9dc8bc60d2357452573908e729

main/src/main/cpp/lz4.cmake

@@ -0,0 +1,7 @@
+set(lz4_srcs
+  lz4.c
+  )
+
+PREPEND(lz4_src_with_path "lz4/lib/" ${lz4_srcs})
+add_library(lz4 ${lz4_src_with_path})
+target_include_directories(lz4 PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/lz4/lib")