pkg/53883: Building webkit-gtk fails on aarch64

[thorpej%me.com@localhost]

>Number:         53883
>Category:       pkg
>Synopsis:       Building webkit-gtk fails on aarch64
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 16 08:20:00 +0000 2019
>Originator:     Jason Thorpe
>Release:        NetBSD 8.99.29 / webkit-gtk/Makefile v 1.155
>Organization:
NetBSD
>Environment:
NetBSD pinebook 8.99.29 NetBSD 8.99.29 (GENERIC64) #2: Sun Dec 30 10:40:26 PST 2018  thorpej@thorpej-mbp13:/Users/thorpej/NetBSD/current/src/sys/arch/evbarm/compile/GENERIC64 evbarm

>Description:
webkit-gtk fails to build on aarch64:

===> Building for webkit-gtk-2.22.5nb1
[  0%] Built target WebKit-forwarding-headers
[  0%] Built target WebKit-fake-api-headers
[  1%] Built target bmalloc
[ 12%] Built target WTFForwardingHeaders
[ 16%] Built target WTF
[ 17%] Built target JavaScriptCoreForwardingHeaders
[ 17%] Built target JSC-fake-api-headers
[ 17%] Built target LLIntOffsetsExtractor
[ 36%] Built target JavaScriptCorePrivateForwardingHeaders
[ 36%] Built target stageSharedScripts
[ 44%] Built target JavaScriptCore
[ 45%] Built target xdgmime
[ 45%] Built target PALForwardingHeaders
[ 46%] Built target PAL
[ 50%] Built target ANGLESupport
[ 50%] Generate bindings (WebCoreBindings)
[ 50%] Built target WebCoreBindings
[ 73%] Built target WebCore
[ 74%] Built target WebCorePlatformGTK
[ 92%] Built target WebKit
gmake[2]: *** No rule to make target 'JavaScriptCore-4.0.gir', needed by 'WebKit2-4.0.gir'.  Stop.
gmake[1]: *** [CMakeFiles/Makefile2:1318: Source/WebKit/CMakeFiles/WebKit2-4-gir.dir/all] Error 2
gmake: *** [Makefile:152: all] Error 2
*** Error code 2

Stop.
make[1]: stopped in /nbsd/pkgsrc/www/webkit-gtk
*** Error code 1

Stop.
make: stopped in /nbsd/pkgsrc/www/webkit-gtk
pinebook:thorpej 29$ 

>How-To-Repeat:
Build webkit-gtk2 on aarch64
>Fix: