OK, looking a bit deeper, the actual error in config.log is:

configure:4739: result: no
configure:4774: checking for conio.h
configure:4781: result: no
configure:4658: checking curses.h usability
configure:4670: gcc -c -g -O2  conftest.c >&5
In file included from conftest.c:54:
/opt/gnu/lib/gcc-lib/hppa2.0w-hp-hpux11.11/3.2.3/include/curses.h:755: syntax error before "va_list"
/opt/gnu/lib/gcc-lib/hppa2.0w-hp-hpux11.11/3.2.3/include/curses.h:756: syntax error before "va_list"
/opt/gnu/lib/gcc-lib/hppa2.0w-hp-hpux11.11/3.2.3/include/curses.h:757: syntax error before "va_list"
/opt/gnu/lib/gcc-lib/hppa2.0w-hp-hpux11.11/3.2.3/include/curses.h:758: syntax error before "va_list"

Adding "#include <varargs.h>" appears to solve the problem.

I'm pretty weak (major understatement) on building configure scripts, but if you create a new one with varargs.h, I'll be happy to test it on my box for you.