pkg/48152: firefox build failure on i386-5.2_STABLE w/modular Xorg

[jdbaker%mylinuxisp.com@localhost]

>Number:         48152
>Category:       pkg
>Synopsis:       firefox build failure on i386-5.2_STABLE w/modular Xorg
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 23 21:40:01 +0000 2013
>Originator:     John D. Baker
>Release:        NetBSD/i386-5.2_STABLE, pkgsrc-2013Q2, X11_TYPE=modular
>Organization:
>Environment:
NetBSD verthandi.technoskunk.fur 5.2_STABLE NetBSD 5.2_STABLE (VERTHANDI) #5: 
Thu Jun 20 15:36:38 CDT 2013  
sysop%verthandi.technoskunk.fur@localhost:/d0/build/netbsd-5/obj/i386/sys/arch/i386/compile/VERTHANDI
 i386

>Description:
Since MesaLib can't cope with native Xorg on netbsd-5, breaking the
majority of applications I expect to use, I bit the bullet and switched
to modular Xorg from pkgsrc-2013Q2.

This has worked for everything up until attempting to build www/firefox.
The build fails as follows:

[...]
/d0/build/pkgsrc/www/firefox/work/mozilla-release/_virtualenv/bin/python 
../../config/expandlibs_exec.py --depend .deps/plugin-container.pp --target 
plugin-container --uselist --  c++ -o plugin-container -I/usr/include 
-I/usr/pkg/include -I/usr/pkg/include/nspr -I/usr/pkg/include/libdrm 
-I/usr/pkg/include/freetype2 -I/usr/pkg/gcc46/include 
-I/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/include -Wall 
-Wpointer-arith -Woverloaded-virtual -Werror=return-type -Wtype-limits 
-Wempty-body -Wsign-compare -Wno-invalid-offsetof -Wcast-align -O2 
-I/usr/include -I/usr/pkg/include -I/usr/pkg/include/nspr 
-I/usr/pkg/include/libdrm -I/usr/pkg/include/freetype2 -I/usr/pkg/gcc46/include 
-I/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/include 
-fno-exceptions -fno-strict-aliasing -Dunix -fno-rtti -ffunction-sections 
-fdata-sections -fno-exceptions -std=gnu++0x -pthread -pipe  -DNDEBUG -DTRIMMED 
-O2 -fomit-frame-pointer MozillaRuntimeMain.o   -lpthread -Wl,-R/usr/pkg/lib/fir
 efox -Wl,-R/usr/pkg/lib 
-L/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3 
-Wl,-R/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3 
-L/usr/pkg/gcc46/lib -Wl,-R/usr/pkg/gcc46/lib -L/usr/lib -Wl,-R/usr/lib 
-L/usr/pkg/lib -L/usr/pkg/lib/nspr -Wl,-R/usr/pkg/lib/nspr -L/usr/pkg/lib/nss 
-Wl,-R/usr/pkg/lib/nss 
-L/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/ 
-Wl,-R/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/ 
-Wl,-z,noexecstack  
-Wl,-rpath-link,/d0/build/pkgsrc/www/firefox/work/mozilla-release/dist/bin 
-Wl,-rpath-link,/usr/pkg/lib    -L../../dist/bin -L../../dist/lib  
-L/d0/build/pkgsrc/www/firefox/work/mozilla-release/dist/bin -lxul -lmozalloc  
-Wl,-R/usr/pkg/lib/nspr -L/usr/pkg/lib/nspr -lplds4 -lplc4 -lnspr4 -pthread  
-Wl,--whole-archive 
/d0/build/pkgsrc/www/firefox/work/mozilla-release/dist/lib/libmozglue.a 
-Wl,--no-whole-archive -rdynamic  -lkvm  -Wl,--export-dynamic 
Executing: c++ -o plugin-container -I/usr/include -I/usr/pkg/include 
-I/usr/pkg/include/nspr -I/usr/pkg/include/libdrm -I/usr/pkg/include/freetype2 
-I/usr/pkg/gcc46/include 
-I/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/include -Wall 
-Wpointer-arith -Woverloaded-virtual -Werror=return-type -Wtype-limits 
-Wempty-body -Wsign-compare -Wno-invalid-offsetof -Wcast-align -O2 
-I/usr/include -I/usr/pkg/include -I/usr/pkg/include/nspr 
-I/usr/pkg/include/libdrm -I/usr/pkg/include/freetype2 -I/usr/pkg/gcc46/include 
-I/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/include 
-fno-exceptions -fno-strict-aliasing -Dunix -fno-rtti -ffunction-sections 
-fdata-sections -fno-exceptions -std=gnu++0x -pthread -pipe -DNDEBUG -DTRIMMED 
-O2 -fomit-frame-pointer 
/d0/build/pkgsrc/www/firefox/work/mozilla-release/ipc/app/tmpmXdp8z.list 
-lpthread -Wl,-R/usr/pkg/lib/firefox -Wl,-R/usr/pkg/lib 
-L/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3 
-Wl,-R/usr/pkg/gcc46/lib/gcc/i386-unkn
 own-netbsdelf5.2./4.6.3 -L/usr/pkg/gcc46/lib -Wl,-R/usr/pkg/gcc46/lib 
-L/usr/lib -Wl,-R/usr/lib -L/usr/pkg/lib -L/usr/pkg/lib/nspr 
-Wl,-R/usr/pkg/lib/nspr -L/usr/pkg/lib/nss -Wl,-R/usr/pkg/lib/nss 
-L/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/ 
-Wl,-R/usr/pkg/gcc46/lib/gcc/i386-unknown-netbsdelf5.2./4.6.3/ 
-Wl,-z,noexecstack 
-Wl,-rpath-link,/d0/build/pkgsrc/www/firefox/work/mozilla-release/dist/bin 
-Wl,-rpath-link,/usr/pkg/lib -L../../dist/bin -L../../dist/lib 
-L/d0/build/pkgsrc/www/firefox/work/mozilla-release/dist/bin -lxul -lmozalloc 
-Wl,-R/usr/pkg/lib/nspr -L/usr/pkg/lib/nspr -lplds4 -lplc4 -lnspr4 -pthread 
-Wl,--whole-archive ../../dist/lib/libmozglue.a -Wl,--no-whole-archive 
-rdynamic -lkvm -Wl,--export-dynamic
/d0/build/pkgsrc/www/firefox/work/mozilla-release/ipc/app/tmpmXdp8z.list:
    INPUT("MozillaRuntimeMain.o")

../../dist/bin/libxul.so: undefined reference to `__sync_sub_and_fetch_4'
collect2: ld returned 1 exit status
gmake[4]: *** [plugin-container] Error 1
gmake[4]: Leaving directory 
`/d0/build/pkgsrc/www/firefox/work/mozilla-release/ipc/app'
gmake[3]: *** [tools] Error 2
gmake[3]: Leaving directory 
`/d0/build/pkgsrc/www/firefox/work/mozilla-release/ipc'
gmake[2]: *** [tools_tier_platform] Error 2
gmake[2]: Leaving directory `/d0/build/pkgsrc/www/firefox/work/mozilla-release'
gmake[1]: *** [tier_platform] Error 2
gmake[1]: Leaving directory `/d0/build/pkgsrc/www/firefox/work/mozilla-release'
gmake: *** [all] Error 2
*** Error code 2

Stop.
make: stopped in /x/pkgsrc/www/firefox
*** Error code 1

Stop.
make: stopped in /x/pkgsrc/www/firefox

>How-To-Repeat:
Attempt to build www/firefox on NetBSD/i386-5.2_STABLE with modular
Xorg (amd64?).
>Fix: