grep-2.5.1: VPATH make from readonly source directory fails

[Michael Deutschmann]

If grep 2.5.1 is built using seperated build and source directories, and
the source directory is not writable, the build will fail.

If no configure options are given, it fails like this:
else \
  echo cat-id-tbl.c changed; \
  rm -f ../../grep-2.5.1/po/cat-id-tbl.c; \
  mv cat-id-tbl.tmp ../../grep-2.5.1/po/cat-id-tbl.c; \
fi
cd ../../grep-2.5.1/po && rm -f stamp-cat-id && echo timestamp > stamp-cat-id
/bin/sh: stamp-cat-id: Permission denied
make[2]: *** [../../grep-2.5.1/po/stamp-cat-id] Error 1
make[2]: Leaving directory `/vol/resv/build/grep-build/po'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/vol/resv/build/grep-build'
make: *** [all] Error 2

If "--disable-nls" is specified on configure, that problem is suppressed,
but a second bug occurs later:

make[2]: Entering directory `/vol/resv/build/grep-build2/doc'
Updating ../../grep-2.5.1/doc/version.texi
cp: cannot create regular file `../../grep-2.5.1/doc/version.texi': Permission 
denied
make[2]: *** [../../grep-2.5.1/doc/stamp-vti] Error 1
make[2]: Leaving directory `/vol/resv/build/grep-build2/doc'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/vol/resv/build/grep-build2'
make: *** [all] Error 2

(Vitals: i386-linux-pc-gnu, GCC 2.95.3, GLIBC 2.1.3, make 3.80)

---- Michael Deutschmann <address@hidden>