Compilation fails on GCC 8.0.1

[uartie]

libva (master) heads/master-0-gd6fd111e2062 ffmpeg (master) heads/master-0-gd176497cec95 libyami (apache) heads/apache-0-g8e941ab610db

GCC 8.0.1 is default on recently released Fedora 28.

$ ./autogen.sh --disable-silent-rules --prefix="/opt/media/install" --enable-tests --enable-debug --enable-h264enc --enable-jpegenc --enable-vp8enc --enable-vp9enc --enable-h265enc --enable-h264dec --enable-jpegdec --enable-vp8dec --enable-vp9dec --enable-h265dec --enable-mpeg2dec --enable-vc1dec --disable-fakedec --disable-oclfilters --enable-dmabuf --enable-md5 --disable-egl --disable-v4l2 --disable-wayland --enable-x11
$ make

h264Parser_unittest.cpp: In member function 'void YamiParser::H264::H264ParserTest::checkH264Pps(YamiParser::H264::Parser&, const YamiParser::H264::NalUnit*)':
h264Parser_unittest.cpp:150:45: error: 'void* memset(void*, int, size_t)' clearing an object of type 'using element_type = std::remove_extent<YamiParser::H264::PPS>::type' {aka 'struct YamiParser::H264::PPS'} with no trivial copy-assignment; use assignment or value-initialization instead [-Werror=class-memaccess]
             memset(pps.get(), 0, sizeof(PPS));
                                             ^
In file included from h264Parser_unittest.cpp:22:
h264Parser.h:292:8: note: 'using element_type = std::remove_extent<YamiParser::H264::PPS>::type' {aka 'struct YamiParser::H264::PPS'} declared here
 struct PPS {
        ^~~
h264Parser_unittest.cpp: In member function 'void YamiParser::H264::H264ParserTest::checkH264SliceHeader(YamiParser::H264::Parser&, YamiParser::H264::NalUnit*)':
h264Parser_unittest.cpp:176:55: error: 'void* memset(void*, int, size_t)' clearing an object of type 'using element_type = std::remove_extent<YamiParser::H264::SliceHeader>::type' {aka 'class YamiParser::H264::SliceHeader'} with no trivial copy-assignment; use assignment or value-initialization instead [-Werror=class-memaccess]
             memset(slice.get(), 0, sizeof(SliceHeader));
                                                       ^
In file included from h264Parser_unittest.cpp:22:
h264Parser.h:371:7: note: 'using element_type = std::remove_extent<YamiParser::H264::SliceHeader>::type' {aka 'class YamiParser::H264::SliceHeader'} declared here
 class SliceHeader {
       ^~~~~~~~~~~
cc1plus: all warnings being treated as errors
make[2]: *** [Makefile:908: unittest-h264Parser_unittest.o] Error 1
make[2]: Leaving directory '/opt/media/build/libyami/codecparsers'
make[1]: *** [Makefile:681: all-recursive] Error 1
make[1]: Leaving directory '/opt/media/build/libyami'
make: *** [Makefile:508: all] Error 2

[uartie]

Fixed by #835