bug#15313: eww fails immediately on browsing ducduckgo

[Eythan Weg]

After starting emacs -Q (commit
20febb474b02edb67ce405ab887076476ea68081) and "M-x eww
anything",  emacs immediately segfault.  I have not
experienced this problem about a month ago.  Here is the
backtrace.

------------------------------------------------------------

Fatal error 11: Segmentation fault
Backtrace:
./src/emacs[0x4f2fdb]
./src/emacs[0x4da07e]
./src/emacs[0x4f1fbe]
./src/emacs[0x4f21c3]
/lib/x86_64-linux-gnu/libpthread.so.0(+0xf210)[0x7f6944e12210]
/usr/lib/x86_64-linux-gnu/libMagickWand.so.5(PixelSetMagickColor+0x17)[0x7f69475f5997]
./src/emacs[0x5b7a7e]
./src/emacs[0x5bb1c5]
./src/emacs[0x5bb60e]
./src/emacs[0x54bc18]
./src/emacs[0x57f273]
./src/emacs[0x54b6ef]
./src/emacs[0x54ba4b]
./src/emacs[0x57f273]
./src/emacs[0x54b6ef]
./src/emacs[0x54ba4b]
./src/emacs[0x54cd1c]
./src/emacs[0x54bb1a]
./src/emacs[0x57f273]
./src/emacs[0x54b11f]
./src/emacs[0x54e1e8]
./src/emacs[0x57fc33]
./src/emacs[0x54b6ef]
./src/emacs[0x54ba4b]
./src/emacs[0x54bd6a]
./src/emacs[0x4df63f]
./src/emacs[0x4df951]
./src/emacs[0x4e0d08]
./src/emacs[0x4e0ddd]
./src/emacs[0x420a20]
./src/emacs[0x4e4cf8]
./src/emacs[0x4e6199]
./src/emacs[0x4e7d0d]
./src/emacs[0x54a0d4]
./src/emacs[0x4da4de]
./src/emacs[0x549fbf]
./src/emacs[0x4de7f7]
./src/emacs[0x4deae2]
./src/emacs[0x4175a5]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5)[0x7f694486a995]
./src/emacs[0x41809c]
...
Segmentation fault