'gegl' segfault breaks gimp build on netbsd-8/amd64

["John D. Baker" <jdbaker%consolidated.net@localhost>]

While trying to get a jump on the freeze for pkgsrc-2019Q1, building
"graphics/gimp" fails due to a segfault in 'gegl'.

First, during the configure phase:

[...]
checking for execinfo.h... (cached) yes
checking for matting engine Levin... [2]   Segmentation fault (core dumped) ${GEGL} --exists...
no (missing GEGL operation "gegl:matting-levin")
checking math.h usability... yes
[...]

Then, during the build phase:

[...]
mkdir -p `dirname 64/gimp-frame.png`; GEGL_USE_OPENCL=no GEGL_SWAP=ram /usr/pkg/bin/gegl ../../icons/Symbolic/64/gimp-frame.png -o 64/gimp-frame.png -- gegl:invert-gamma
[1]   Segmentation fault (core dumped) GEGL_USE_OPENCL=...
gmake[3]: *** [Makefile:2409: 64/gimp-error.png] Error 139
gmake[3]: *** Waiting for unfinished jobs....
[1]   Segmentation fault (core dumped) GEGL_USE_OPENCL=...
gmake[3]: *** [Makefile:2409: 64/gimp-question.png] Error 139
[1]   Segmentation fault (core dumped) GEGL_USE_OPENCL=...
gmake[3]: *** [Makefile:2409: 64/gimp-frame.png] Error 139
[1]   Segmentation fault (core dumped) GEGL_USE_OPENCL=...
gmake[3]: *** [Makefile:2409: 64/gimp-warning.png] Error 139
[1]   Segmentation fault (core dumped) GEGL_USE_OPENCL=...
gmake[3]: *** [Makefile:2409: 64/gimp-info.png] Error 139
gmake[3]: Leaving directory '/tmp/pkgsrc/graphics/gimp/work/gimp-2.10.8/icons/Symbolic-Inverted'
gmake[2]: *** [Makefile:723: all-recursive] Error 1
gmake[2]: Leaving directory '/tmp/pkgsrc/graphics/gimp/work/gimp-2.10.8/icons'
gmake[1]: *** [Makefile:858: all-recursive] Error 1
gmake[1]: Leaving directory '/tmp/pkgsrc/graphics/gimp/work/gimp-2.10.8'
gmake: *** [Makefile:759: all] Error 2
*** Error code 2

Stop.
make[1]: stopped in /x/pkgsrc/graphics/gimp
*** Error code 1

Stop.
make: stopped in /x/pkgsrc/graphics/gimp


The only core file lying around is:

  ${WRKOBJDIR}/graphics/gimp/work/gimp-2.10.8/icons/Symbolic-Inverted/gegl.core

and when loaded with 'gdb', the backtrace is minimal:

[...]
Reading symbols from gegl...done.
[New process 1]
Core was generated by `gegl'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x000000000000f73c in ?? ()
(gdb) bt
#0  0x000000000000f73c in ?? ()
#1  0x0000744c970026a4 in ?? () from /usr/lib/libgcc_s.so.1
#2  0x0000744ca42b1360 in ?? ()
#3  0x0000744c97002399 in _init () from /usr/lib/libgcc_s.so.1
#4  0x0000000000000000 in ?? ()


This is on the most up-to-date 8.0_STABLE for amd64.

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