remove lrt in mac environment

add weak symbol _RegisterThriftProtocol in mac
fix the version get in the latest MacOS 10.13+

CMakeLists.txt

@@ -158,7 +158,6 @@ set(DYNAMIC_LIB
     ${PROTOC_LIB}
     ${CMAKE_THREAD_LIBS_INIT}
     ${THRIFT_LIB}
-    rt
     ${SSL_LIB}
     ${CRYPTO_LIB}
     dl
@@ -183,7 +182,8 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
         "-framework Foundation"
         "-Wl,-U,_MallocExtension_ReleaseFreeMemory"
         "-Wl,-U,_ProfilerStart"
-        "-Wl,-U,_ProfilerStop")
+        "-Wl,-U,_ProfilerStop"
+        "-Wl,-U,_RegisterThriftProtocol")
 endif()
 
 # for *.so

config_brpc.sh

@@ -276,7 +276,7 @@ if [ ! -z "$DEBUGSYMBOLS" ]; then
 fi
 if [ "$SYSTEM" = "Darwin" ]; then
     CPPFLAGS="${CPPFLAGS} -Wno-deprecated-declarations"
-    version=`system_profiler SPSoftwareDataType | grep "System Version" | awk '{print $5}' | awk -F. '{printf "%d.%d", $1, $2}'`
+    version=`sw_vers -productVersion | awk -F '.' '{print $1 "." $2}'`
     if [[ `echo "$version<10.12" | bc -l` == 1 ]]; then
         CPPFLAGS="${CPPFLAGS} -DNO_CLOCK_GETTIME_IN_MAC"
     fi

src/brpc/global.cpp

@@ -77,6 +77,7 @@
 extern "C" {
 // defined in gperftools/malloc_extension_c.h
 void BAIDU_WEAK MallocExtension_ReleaseFreeMemory(void);
+void BAIDU_WEAK RegisterThriftProtocol();
 }
 
 namespace brpc {
@@ -97,7 +98,6 @@ using namespace policy;
 
 const char* const DUMMY_SERVER_PORT_FILE = "dummy_server.port";
 
-void __attribute__((weak)) RegisterThriftProtocol();
 
 struct GlobalExtensions {
     GlobalExtensions()
@@ -467,9 +467,8 @@ static void GlobalInitializeOrDieImpl() {
     }
 
     // Register Thrift framed protocol if linked
-
-    if (brpc::RegisterThriftProtocol) {
-        brpc::RegisterThriftProtocol();
+    if (RegisterThriftProtocol) {
+        RegisterThriftProtocol();
     }
 
     // Only valid at client side