intl: Add --enable-host-shared support [PR100096]

intl: Add --enable-host-shared support [PR100096]

As mentioned in the PR, building gcc with jit enabled and
--enable-host-shared doesn't work on NetBSD/i?86, as libgccjit.so.0
has text relocations.
The r0-125846-g459260ecf8b420b029601a664cdb21c185268ecb changes
added --enable-host-shared support to various libraries, but didn't
add it to intl/ subdirectory; on Linux it isn't really needed, because
all: all-no
all-no: #nothing
but on other OSes intl/libintl.a is built.

The following patch makes sure it is built with -fPIC when
--enable-host-shared is used.

2021-04-16  Jakub Jelinek  <jakub@redhat.com>

	PR jit/100096
	* configure.ac: Add --enable-host-shared support.
	* Makefile.in: Update copyright.  Add @PICFLAG@ to CFLAGS.
	* configure: Regenerated.

(cherry picked from commit 4a1493f0603262a7dc1114d9827353e9810e63dc)