To have your source preprocessed, create a file called htsource.pre in
your source directory, and type the preprocessor name.
For example:
tee htsource.pre
gcc -E -x c
^D
To assign a post processor (for example, to convert XML to HTML via XSLT)
do the same with a file called htout.pre.
Since the latter needs to be called again and again, it is not supported
in mod_perl.
