Oh, found the problem : if gawk isn't found, then the configure script still ends happily, so you can go on compiling ; but when you try to install, for the install target of freedroidRPG, then there's a problem because AWK=''. But that error doesn't make "make" unhappy either! So you end up with a failed install, even though there's no reported error. You have to check in the logs to find out about it.

For the Debian package, I'll apply change the following configure.ac line:
AC_PATH_PROG([AWK], [gawk], [])    dnl GNU version of awk awk is needed in some po/ scripts

to:
AC_PATH_PROGS([AWK], [gawk mawk], [])

I haven't seen the problem with mawk and the po/ scripts...