compile error: filei.cc:54:4: error: ‘::bzero’ has not been declared

[hisnameishb]

After
sh autogen.sh CFLAGS= CXXFLAGS=-O3

make doesnt run through:
make make all-am make[1]: entering di „/foo/ua“ g++ -DHAVE_CONFIG_H -I. -O3 -MT filei.o -MD -MP -MF .deps/filei.Tpo -c -o filei.o filei.cc In file included from /usr/include/c++/5/ext/hash_set:60:0, from ./filei.h:58, from filei.cc:35: /usr/include/c++/5/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header which may be removed without further notice at a future date. Please use a non-deprecated interface with equivalent functionality instead. For a listing of replacement headers and interfaces, consult the file backward_warning.h. To disable this warning use -Wno-deprecated. [-Wcpp] #warning \ ^ filei.cc: In constructor ‘filei::filei(const string&, bool, bool, size_t, size_t)’: filei.cc:54:4: error: ‘::bzero’ has not been declared ::bzero(_md5,16); // zero out ^ Makefile:439: Rule for destination „filei.o“ failed make[1]: *** [filei.o] Errors 1 make[1]: Dir „/foo/ua“ exiting Makefile:325: Rule for Destination „all“ failed make: *** [all] Errors 2

Tried this under Ubuntu 16.04 32-Bit