Fix multi-file installation for files in srcdir. For files that can live in the build tree or the source tree, we have to expect that prepending `$(srcdir)/' to each name will let the install command line exceed length limitations. Thus use a new macro, $(am__base_list), to install in chunks of 40 files, similar to what we do for nobase_* files. There, lower the limit to 40, too. * lib/am/inst-vars.am (am__install_max): Lower to 40. (am__base_list): New macro. * lib/am/data.am (install-%DIR%%PRIMARY%) [%?BASE%]: Use it. * lib/am/texinfos.am (install-dvi-am, install-html-am) (install-info-am, install-pdf-am, install-ps-am): Likewise. Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>