grep-2.5.3: build from readonly source directory fails

[Michael Deutschmann]

Presently, building grep from a readonly source directory (via the VPATH
feature) does not work.  On an ordinary build, the Makefile attempts to
write the file "doc/stamp-vti" in the source directory.

It seems the Makefile expects that precompiled info files are to be
distributed in the source directory, as is typical for GNU software -- so
Makefile rules that write into $(srcdir) are OK since they will only
trigger when the documentation is changed on the maintainer's own system.
Unfortunately, it seems that the precompiled info file(s) and supporting
version.texi file are not actually present in the grep-2.5.3 distribution.

(Actually, this is only when the --disable-nls option is given to
configure -- otherwise the build similarly crashes earlier trying to write
"po/stamp-cat-id" in the source directory.)

---- Michael Deutschmann <address@hidden>