Support Botan-2 (>= 2.2.0). Fix #104

Botan-2 2.2.0 has not been released yet. I've tested with their `master`
branch code and verified that the issue #104 is resolved.

CMakeLists.txt

@@ -5,6 +5,7 @@ project(QtShadowsocks
         LANGUAGES CXX)
 
 option(BUILD_SHARED_LIBS "Build ${PROJECT_NAME} as a shared library" ON)
+option(USE_BOTAN2 "Build ${PROJECT_NAME} with Botan-2" OFF)
 
 set(LIB_INSTALL_DIR ${CMAKE_INSTALL_PREFIX}/lib
     CACHE PATH "Installation directory for libraries")
@@ -18,7 +19,15 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 find_package(Qt5Core)
 find_package(Qt5Network)
 find_package(PkgConfig)
-pkg_search_module(BOTAN REQUIRED botan-1.10 botan-2)
+
+if (USE_BOTAN2)
+    pkg_check_modules(BOTAN REQUIRED botan-2>=2.2.0)
+else()
+    pkg_check_modules(BOTAN REQUIRED botan-1.10)
+endif()
+find_library(BOTAN_LIBRARY_VAR
+             NAMES ${BOTAN_LIBRARIES}
+             HINTS ${BOTAN_LIBRARY_DIRS} ${BOTAN_LIBDIR})
 
 if(NOT BUILD_SHARED_LIBS)
     add_definitions(-DQSS_STATIC)

lib/CMakeLists.txt

@@ -46,7 +46,7 @@ add_library(${LIBNAME} ${SOURCE})
 target_link_libraries(${LIBNAME}
     PUBLIC Qt5::Core
     PUBLIC Qt5::Network
-    PRIVATE ${BOTAN_LIBRARIES})
+    PRIVATE ${BOTAN_LIBRARY_VAR})
 target_include_directories(${LIBNAME} PRIVATE ${BOTAN_INCLUDE_DIRS})
 
 foreach(LIB Qt5Network Qt5Core ${BOTAN_LIBRARIES})

shadowsocks-libqss/CMakeLists.txt

@@ -8,9 +8,8 @@ set(SOURCE
 
 add_executable(${TASK} ${SOURCE})
 
-target_link_libraries(${TASK} Qt5::Core Qt5::Network ${BOTAN_LIBRARIES} QtShadowsocks)
+target_link_libraries(${TASK} Qt5::Core Qt5::Network QtShadowsocks)
 target_include_directories(${TASK}
-    PUBLIC ${BOTAN_INCLUDE_DIRS}
     PUBLIC ${PROJECT_SOURCE_DIR}/lib)
 
 install(TARGETS ${TASK} RUNTIME DESTINATION bin)

test/CMakeLists.txt

@@ -12,7 +12,6 @@ set(SOURCE
 add_executable(${TASK} ${SOURCE})
 
 find_package(Qt5Test)
-target_link_libraries(${TASK} Qt5::Core Qt5::Network Qt5::Test ${BOTAN_LIBRARIES} QtShadowsocks)
+target_link_libraries(${TASK} Qt5::Core Qt5::Network Qt5::Test QtShadowsocks)
 target_include_directories(${TASK}
-    PUBLIC ${BOTAN_INCLUDE_DIRS}
     PUBLIC ${PROJECT_SOURCE_DIR}/lib)