[Fontconfig] Got stuck making release

[Patrick Lam]

make distcheck fails on the doc directory.  At first, there's an
apparently bogus value for DOCSRC in Makefile.am; I tried replacing it
with DOCSRC=doc, but then it still fails with 'No rule to make target
`fonts-conf.5', needed by `distdir'.  Stop'.  Help!  I have insufficient
build-fu.

In fact the doc directory is completely empty in the fontconfig-2.3.90/
subdirectory.

pat