Build environment incomplete and how to handle that.

[Harald Barth <haba@pdc.kth.se>]

I compiled heimdal on a box that was not installed with all the devel
tools. I run configure and then make and got the following error:

gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wbad-function-cast -Wmissing-declarations -Wnested-externs -g -O2 -o testit testit.o  ./.libs/libeditline.a ../../lib/vers/.libs/libvers.a ../../lib/roken/.libs/libroken.a -lcrypt -lresolv
./.libs/libeditline.a(editline.o): In function `TTYinfo':
clear_line/editline.c:245: undefined reference to `tgetent'
clear_line/editline.c:250: undefined reference to `tgetstr'
clear_line/editline.c:255: undefined reference to `tgetnum'
clear_line/editline.c:256: undefined reference to `tgetnum'
collect2: ld returned 1 exit status

So, what is wrong? Couldn't configue have told me that it's no idea in
starting make without curses (I needed ncurses-devel). The same goes
for lex and yacc. At the end of the configure run, show a summary of
things to fix instead of failing the make later with some strange
message from linker or other tool.

Harald.