[krbdev.mit.edu #1188] aclocal.m4 should use AC_CONFIG_FILES

[Ezra Peisach via RT]

In autoconf 2.52 and up, the use of AC_OUTPUT with a list of
files is deprecated by the use of AC_CONFIG_FILES.

In order to use this, we need to do away with the for loop 
in K5_GEN_MAKEFILE code - as it confuses the AC_CONFIG_FILES - it 
only allows one to specify a file one time.

The added benefit, is that eventually, we will be able to 
do something like "./config.status lib/Makefile" and have it
generate the proper Makefile.

I have a simple patch that replaces AC_OUTPUT by AC_CONFIG_FILES that
works. The only problem is that for the code to generate a single Makefile,
krb5_pre_in and krb5_post_in cannot be shell variables and must be
expanded when the configure script is made. I am working on this now.

Initially - this change reduces the size of configure by 20-40K depending
on the number of subdirs having Makefiles output.