Running this command
portupgrade -p -o print/ghostscript9 print/ghostscript8
I've got this error during the build:
/bin/sh <./obj/../soobj/ldt.tr
./obj/../soobj/gdevl256.o(.text+0x73a): In function `gs_shared_init':
./base/gdevl256.c:310: multiple definition of `gs_shared_init'
./obj/../soobj/gdevxalt.o(.text+0x1759):./base/gdevxalt.c:851: first defined here
/usr/bin/ld: Warning: size of symbol `gs_shared_init' changed from 150 in ./obj/../soobj/gdevxalt.o to 38 in ./obj/../soobj/gdevl256.o
./obj/../soobj/gdevvglb.o(.text+0x995): In function `gs_shared_init':
./base/gdevvglb.c:375: multiple definition of `gs_shared_init'
./obj/../soobj/gdevxalt.o(.text+0x1759):./base/gdevxalt.c:851: first defined here
gmake[1]: *** [bin/../sobin/libgs.so.9.02] Error 1
gmake[1]: Leaving directory `/usr/ports/print/ghostscript9/work/ghostscript-9.02'
gmake: *** [so] Error 2
*** Error code 1

Stop in /usr/ports/print/ghostscript9.
*** Error code 1

Stop in /usr/ports/print/ghostscript9.
** Command failed [exit code 1]: /usr/bin/script -qa /tmp/portupgrade20110716-49093-1hg0ara-0 env UPGRADE_TOOL=portupgrade UPGRADE_PORT=ghostscript8-8.71_8 UPGRADE_PORT_VER=8.71_8 make WITH_A4SIZE=1 WITH_SVGALIB=1 WITH_ICONV=1 WITH_FONTCONFIG=1 DEPENDS_TARGET=package
** Fix the problem and try again.
** Listing the failed packages (-:ignored / *:skipped / !:failed)
	! print/ghostscript9 (ghostscript8-8.71_8)	(new compiler error)



So, googling for "multiple definition of `gs_shared_init'" I've found a PR I've posted 4 years ago as 1st result: ports/115593.
Unfortunately, unlike with ghostscript-gpl, it is failing also with just one knob (GS_lvga256 and GS_vgalib) selected and also unchecking GS_display, like in the patch for the old PR (?).
So I finally had it built unchecking both GS*vga* knobs.

How-To-Repeat: # cd /usr/ports/print/ghostscript9
# make

with a "clean" config
or with one or both GS_lvga256 and GS_vgalib knob checked
or maybe passing WITH_SVGALIB to make