Omitting libraries if empty?

[John Gruenenfelder]

I have a project which uses all three of the autotools.  Following the
examples given in the Autobook, one of my library subdirectories is "replace"
containing functions which will be conditionally compiled if the system does
not have them.

The problem I am having occurs when there are no files to be compiled in
replace.  On my Debian machine, this does not cause any trouble; ar allows an
archive to be created with no members, and the linker will accept an empty
library and ignore it.

Other systems, however, choke on this such as IRIX and OSX.  How can I make
it so that libreplace.la is NOT used, nor compiled, if there is nothing to put
into it?

My main Makefile.am lists "replace" in the SUBDIRS variable.  Each of my
subdirectories' Makefiles list libreplace.la in their fo_LDADD variables.  How
can I make this conditional?


-- 
--John Gruenenfelder    Research Assistant, Steward Observatory, U of Arizona
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