Can't build with posix utmpx on Haiku

[khallebal]

Hello
The problem i'm having is related to utmpx.h, i don't know why i'm getting these errors even though
Haiku has the posix version of it, what am i missing?
This is the error:

/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp: In member function void KPty::login(const char*, const char*)':
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:528:26: error: 'struct utmpx' has no member named 'ut_host'
         strncpy(l_struct.ut_host, remotehost, sizeof(l_struct.ut_host));
                          ^~~~~~~
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:528:63: error: 'struct utmpx' has no member named 'ut_host'
         strncpy(l_struct.ut_host, remotehost, sizeof(l_struct.ut_hos));
                                                               ^~~~~~
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:571:15: error: '_PATH_UTMPX' was not declared in this scope
     utmpxname(_PATH_UTMPX);
               ^~~~~~~~~~~
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:571:15: note: suggested alternative: 'HAVE_UTMPX'
     utmpxname(_PATH_UTMPX);
               ^~~~~~~~~~~
               HAVE_UTMPX
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:571:5: error: 'utmpxname' was not declared in this scope
     utmpxname(_PATH_UTMPX);
     ^~~~~~~~~
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:571:5: note: suggested alternative: 'tmpnam'
     utmpxname(_PATH_UTMPX);
     ^~~~~~~~~
     tmpnam
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp: In member function void KPty::logout()':
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:627:15: error: '_PATH_UTMPX' was not declared in this scope
     utmpxname(_PATH_UTMPX);
               ^~~~~~~~~~~
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:627:15: note: suggested alternative: 'HAVE_UTMPX'
     utmpxname(_PATH_UTMPX);
               ^~~~~~~~~~~
               HAVE_UTMPX
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:627:5: error: 'utmpxname' was not declared in this scope
     utmpxname(_PATH_UTMPX);
     ^~~~~~~~~
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:627:5: note: suggested alternative: 'tmpnam'
     utmpxname(_PATH_UTMPX);
     ^~~~~~~~~
     tmpnam
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:640:20: error: 'struct utmpx' has no member named 'ut_host'
         memset(ut->ut_host, 0, sizeof(*ut->ut_host));
                    ^~~~~~~
/boot/home/Desktop/work/qtermwidget/lib/kpty.cpp:640:44: error: 'struct utmpx' has no member named 'ut_host'
         memset(ut->ut_host, 0, sizeof(*ut->ut_host));

I am building with gcc-8.3.0 and Qt-5.15, if you need more info please let me know.