fix c++17 build error

Author: outman-zhou

mars/comm/assert/__assert.c

@@ -38,9 +38,8 @@ void __assert_rtn(const char *, const char *, int, const char *) __dead2;
 EXPORT_FUNC void __ASSERT(const char * _pfile, int _line, const char * _pfunc, const char * _pexpression) {
     XLoggerInfo info= {0};
     char assertlog[4096] = {'\0'};
-    int offset = 0;
 
-    offset += snprintf(assertlog, sizeof(assertlog), "[ASSERT(%s)]", _pexpression);
+    snprintf(assertlog, sizeof(assertlog), "[ASSERT(%s)]", _pexpression);
 
 //#ifdef ANDROID
 //    android_callstack(assertlog+offset, sizeof(assertlog)-offset);