can't compile xwpe 1.5.20a on Solaris 2.6

[aleXXX <alexander.neundorf@rz.tu-ilmenau.de>]

That's it.
The compiler says:

...
gcc blah -c we_unix.c
In file included from /usr/local/include/curses.h:56
                 from we_unix.c:26:
/usr/local/include/sgtty.h:20: warning: 'HUPCL' redefined
/usr/include/sys/termios.h:265: warning: this is the location of the
previous definition

blah
and so on with many other stuff like XTABS, ECHO, CR1 and so on.
then:

In file included from /usr/local/include/termios.h:13:
                 from we_unix.c:18:
/usr/include/sys/termios.h:376: parse error before 'uint32_t'
/usr/include/sys/termios.h:376: warning: no semicolon at end of struct
or union
In file included from edit.h:22
                 from we_unix.c:30:
/usr/local/include/string.h:30: parse error before '('
/usr/local/include/string.h:30: parse error before 'void'
make: *** [we_unix.o] Error 1

What's wrong ?

bye
alex