add linker flag to liblog makefile

src/lib/log/Makefile.am

@@ -23,6 +23,8 @@ liblog_la_SOURCES += root_logger_name.cc root_logger_name.h
 liblog_la_SOURCES += strutil.h strutil.cc
 liblog_la_SOURCES += xdebuglevel.cc xdebuglevel.h
 
+liblog_la_LDFLAGS = $(LOG4CXX_LDFLAGS)
+
 # Note: the ordering matters: -Wno-... must follow -Wextra (defined in
 # B10_CXXFLAGS)
 liblog_la_CXXFLAGS = $(AM_CXXFLAGS)