graphics/ImageMagick6: Strip shared library

- Bump PORTREVISION for package change

====> Running Q/A tests (stage-qa)
Warning: 'lib/perl5/site_perl/mach/5.40/auto/Image/Magick/Q16/Q16.so' is not stripped consider trying INSTALL_TARGET=install-strip or using ${STRIP_CMD}

PR:		290596
Approved by:	arrowd

graphics/ImageMagick6/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	ImageMagick
 DISTVERSION=	6.9.13-23
-PORTREVISION=	5
+PORTREVISION=	6
 PORTEPOCH=	1
 CATEGORIES=	graphics perl5
 MASTER_SITES=	https://ftp.acc.umu.se/mirror/imagemagick.org/ftp/releases/ \
@@ -341,6 +341,9 @@ post-install:
 		${STAGEDIR}${PREFIX}/etc/ImageMagick-6/${i}.sample
 .endfor
 
+post-install-PERL-on:
+	${STRIP_CMD} ${STAGEDIR}${SITE_ARCH}/auto/Image/Magick/*/*.so
+
 do-test:
 	-cd ${WRKSRC} && ${SETENV} ${MAKE_ENV} limits -m 20m ${MAKE} ${_MAKE_JOBS} check