Firefox build fails

[AN]

Hi:

FreeBSD BSD_12 12.0-CURRENT FreeBSD 12.0-CURRENT #13 r313546: Fri Feb 
10 10:04:11 EST 2017     root at BSD_12:/usr/obj/usr/src/sys/MYKERNEL  amd64


Trying to install Firefox fails with the following:

../../js/src/jsarray.o: In function 
`js::NewFullyAllocatedArrayTryReuseGroup(JSContext*, JSObject*, unsigned 
long, js::NewObjectKind, bool)':
/usr/ports/www/firefox/work/firefox-51.0.1/js/src/jsarray.cpp:(.text._ZN2js35NewFullyAllocatedArrayTryReuseGroupEP9JSContextP8JSObjectmNS_13NewObjectKindEb+0xb59): 
undefined reference to `__dtraceenabled_javascript___object__create'
/usr/bin/ld: ../../js/src/jsarray.o: relocation R_X86_64_PC32 against 
`__dtraceenabled_javascript___object__create' can not be used when making 
a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
c++: error: linker command failed with exit code 1 (use -v to see 
invocation)
gmake[7]: *** 
[/usr/ports/www/firefox/work/firefox-51.0.1/config/rules.mk:802: 
libxul.so] Error 1
gmake[7]: Leaving directory 
'/usr/ports/www/firefox/work/firefox-51.0.1/obj-x86_64-unknown-freebsd12.0/toolkit/library'
gmake[6]: *** 
[/usr/ports/www/firefox/work/firefox-51.0.1/config/recurse.mk:71: 
toolkit/library/target] Error 2
gmake[6]: Leaving directory 
'/usr/ports/www/firefox/work/firefox-51.0.1/obj-x86_64-unknown-freebsd12.0'
gmake[5]: *** 
[/usr/ports/www/firefox/work/firefox-51.0.1/config/recurse.mk:33: compile] 
Error 2
gmake[5]: Leaving directory 
'/usr/ports/www/firefox/work/firefox-51.0.1/obj-x86_64-unknown-freebsd12.0'
gmake[4]: *** 
[/usr/ports/www/firefox/work/firefox-51.0.1/config/rules.mk:523: default] 
Error 2
gmake[4]: Leaving directory 
'/usr/ports/www/firefox/work/firefox-51.0.1/obj-x86_64-unknown-freebsd12.0'
gmake[3]: *** [/usr/ports/www/firefox/work/firefox-51.0.1/client.mk:413: 
realbuild] Error 2
gmake[3]: Leaving directory '/usr/ports/www/firefox/work/firefox-51.0.1'
gmake[2]: *** [/usr/ports/www/firefox/work/firefox-51.0.1/client.mk:168: 
build] Error 2
gmake[2]: Leaving directory '/usr/ports/www/firefox/work/firefox-51.0.1'
===> Compilation failed unexpectedly.


Any help fixing this would be really appreciated.  Thanks in advance.

Regards