Only link the library when it's existed (#333)

CMakeLists.txt

@@ -50,9 +50,12 @@ configure_file(src/version.h.in ${PROJECT_BINARY_DIR}/version.h)
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     set(CMAKE_EXE_LINKER_FLAGS "-static-libgcc -static-libstdc++")
 endif()
+
+find_library(UNWIND_LIB unwind)
+
 add_executable(kvrocks )
 target_compile_features(kvrocks PRIVATE cxx_std_11)
-target_compile_options(kvrocks PRIVATE -Wall -Wpedantic -g -Wsign-compare -Wreturn-type -fno-omit-frame-pointer -lunwind -O0)
+target_compile_options(kvrocks PRIVATE -Wall -Wpedantic -g -Wsign-compare -Wreturn-type -fno-omit-frame-pointer -O0)
 option(ENABLE_ASAN "enable ASAN santinizer" OFF)
 if(ENBALE_ASAN)
     target_compile_options(kvrocks PRIVATE -fsanitize=address)
@@ -70,6 +73,9 @@ if(CMAKE_THREAD_LIBS_INIT)
 endif()
 target_link_libraries(kvrocks PRIVATE -fno-omit-frame-pointer)
 target_link_libraries(kvrocks ${EXTERNAL_LIBS})
+if(UNWIND_LIB)
+    target_link_libraries(kvrocks PRIVATE -lunwind)
+endif()
 target_sources(kvrocks PRIVATE
         src/cluster.cc
         src/cluster.h
@@ -149,7 +155,7 @@ target_sources(kvrocks PRIVATE
 # kvrocks2redis sync tool
 add_executable(kvrocks2redis)
 target_compile_features(kvrocks2redis PRIVATE cxx_std_11)
-target_compile_options(kvrocks2redis PRIVATE -Wall -Wpedantic -g -Wsign-compare -Wreturn-type -lunwind)
+target_compile_options(kvrocks2redis PRIVATE -Wall -Wpedantic -g -Wsign-compare -Wreturn-type)
 option(ENABLE_ASAN "enable ASAN santinizer" OFF)
 if(ENBALE_ASAN)
     target_compile_options(kvrocks2redis PRIVATE -fno-omit-frame-pointer -fsanitize=address)
@@ -158,6 +164,9 @@ endif()
 add_dependencies(kvrocks2redis libevent glog rocksdb)
 target_include_directories(kvrocks2redis PRIVATE ${PROJECT_BINARY_DIR})
 target_include_directories(kvrocks2redis ${EXTERNAL_INCS})
+if(UNWIND_LIB)
+    target_link_libraries(kvrocks2redis PRIVATE -lunwind)
+endif()
 
 find_package(Threads REQUIRED)
 if(THREADS_HAVE_PTHREAD_ARG)
@@ -332,9 +341,11 @@ add_executable(unittest
 
 add_dependencies(unittest glog rocksdb snappy jemalloc)
 target_compile_features(unittest PRIVATE cxx_std_11)
-target_compile_options(unittest PRIVATE -lunwind)
 message(${snappy_LIBRARIES})
 target_link_libraries(unittest PRIVATE ${EXTERNAL_LIBS} -lgtest)
+if(UNWIND_LIB)
+    target_link_libraries(unittest PRIVATE -lunwind)
+endif()
 target_include_directories(unittest PRIVATE ${PROJECT_BINARY_DIR})
 target_include_directories(unittest ${EXTERNAL_INCS})
 target_include_directories(unittest PRIVATE src)