bootstrap: make first char of IFS a space.

bootstrap: make first char of IFS a space.

Putting tab first in IFS breaks func_echo_all usage of $*,
resulting in failure of func_infer_tag to match a command line
using a $CC with trailing spaces. The trailing spaces were
stripped out of CC_expanded but words in $CC were separated by
tabs. This didn't match the makefile expansion of $CC using the
standard IFS with a first char of space.
* gl/build-aux/funclib.sh (IFS): Make first char a space.
* bootstrap: Regenerate.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>