Makefile and SHELL

Hello

In Makefile.in, we enforce bash with SHELL=/usr/bin/env bash, but we state  
that the build should be posix enabled (at least I was told that :)) , so  
why not SHELL=/usr/bin/env sh or SHELL=/bin/sh (or nothing, since latter  
is default) ?
I understand that some scripts still need bash, but they have the right  
shebang line and SHELL will be the default shell used by $(shell...)  
command, no ?
Moreover, in Makefile.gbuild we have :
ifdef gb_SHELL
SHELL := $(gb_SHELL)
else
SHELL := /bin/sh
endif
So SHELL in global makefile is only used for sources.ver from tarball and  
to echo the version to sed, so we can :
- remove the SHELL assignment in Makefile.in
- remove the else part of the ifdef in Makefile.gbuild

regards
--
Mat M