[PATCH] Makefile: set PERL_PATH and SHELL_PATH unconditionally

Do not check whether PERL_PATH and SHELL_PATH are undefined before setting their default values. This prevents them from being set via environment variables.

Signed-off-by: Matt Kraai <kraai@ftbfs.org>
---
 On Mon, Oct 19, 2009 at 11:36:26PM -0700, Junio C Hamano wrote:
 > Matt Kraai <kraai@ftbfs.org> writes:
 > 
 > > The top-level Makefile currently contains
 > >
 > >> ifndef SHELL_PATH
 > >> 	SHELL_PATH = /bin/sh
 > >> endif
 > >> ifndef PERL_PATH
 > >> 	PERL_PATH = /usr/bin/perl
 > >> endif
 > >
 > > The checks are only necessary if these variables need to be overridden
 > > by environment variables, not just via the make command line.  Is this
 > > the case?
 > 
 > It may not have been the original intention, but the above would mean that
 > some people may have learned to run "SHELL_PATH=/bin/ksh make" and
 > changing it would break things for them, no?

 Yes, that's what I was concerned about.  This appears to be possible
 for PERL_PATH on all platforms and for SHELL_PATH on platforms other
 than SCO UnixWare, SunOS, and IRIX.

 > I do not think changing them is bad per-se, but we would need to add extra
 > warnings in the release note to explain this change, that's all.  This
 > would only affect people who build from the source (including distro
 > people) so it is not really a big deal.

 I hope this patch is OK.

 Documentation/RelNotes-1.6.6.txt |    3 +++
 Makefile                         |    8 ++------
 2 files changed, 5 insertions(+), 6 deletions(-)