* automake.in (&handle_source_transform): Calculate a default file for use in the absence of an appropriate _SOURCES declaration by first stripping any suffix from the unxformed target name, and appending `.c'. * doc/automake.texi (Program Sources, Libtool Modules): Document this. * tests/ltlibsrc.test: New file. * tests/Makefile.am (TESTS): Add ltlibsrc.test.