Well, I tried to build Firefox 3 after updating all the other ports, it gets to this point and fails:

c++ -o nsBlockFrame.o -c -I../../dist/include/system_wrappers -include ../../config/gcc_hidden.h -DMOZILLA_INTERNAL_API -D_IMPL_NS_COM -DEXPORT_XPT_API -DEXPORT_XPTC_API -D_IMPL_NS_COM_OBSOLETE -D_IMPL_NS_GFX -D_IMPL_NS_WIDGET -DIMPL_XREAPI -DIMPL_NS_NET -DIMPL_THEBES -DOSTYPE=\"FreeBSD7\" -DOSARCH=FreeBSD -D_IMPL_NS_LAYOUT -I. -I./../base -I./../forms -I./../tables -I./../xul/base/src -I./../../content/xul/content/src -I./../../content/base/src -I./../../content/html/content/src -I./../../dom/src/base -D_THREAD_SAFE -I/usr/local/include/cairo -I/usr/local/include/freetype2 -I/usr/local/include -I/usr/local/include/pixman-1 -D_THREAD_SAFE -I/usr/local/include/cairo -I/usr/local/include -I/usr/local/include/freetype2 -I/usr/local/include/pixman-1 -I. -I. -I../../dist/include/xpcom -I../../dist/include/string -I../../dist/include/dom -I../../dist/include/content -I../../dist/include/thebes -I../../dist/include/gfx -I../../dist/include/widget -I../../dist/include/locale -I../../dist/include/view -I../../dist/include/necko -I../../dist/include/js -I../../dist/include/caps -I../../dist/include/pref -I../../dist/include/htmlparser -I../../dist/include/webshell -I../../dist/include/plugin -I../../dist/include/docshell -I../../dist/include/webbrwsr -I../../dist/include/oji -I../../dist/include/unicharutil -I../../dist/include/lwbrk -I../../dist/include/imglib2 -I../../dist/include/xpconnect -I../../dist/include/java -I../../dist/include/intl -I../../dist/include/thebes -I../../dist/include/cairo -I../../dist/include/accessibility -I../../dist/include -I../../dist/include/layout -I/usr/local/include/nspr -I/usr/local/include -I/usr/include -I../../dist/sdk/include -I/usr/local/include -fPIC -I/usr/local/include -I/usr/local/include -fno-rtti -fno-exceptions -Wall -Wconversion -Wpointer-arith -Woverloaded-virtual -Wsynth -Wno-ctor-dtor-privacy -Wno-non-virtual-dtor -Wcast-align -Wno-long-long -O -pipe -O2 -fno-strict-aliasing -O2 -fno-strict-aliasing -fshort-wchar -pipe -DNDEBUG -DTRIMMED -O2 -D_THREAD_SAFE -I/usr/local/include/gtk-2.0 -I/usr/local/lib/gtk-2.0/include -I/usr/local/include/atk-1.0 -I/usr/local/include/cairo -I/usr/local/include/pango-1.0 -I/usr/local/include -I/usr/local/include/glib-2.0 -I/usr/local/lib/glib-2.0/include -I/usr/local/include/freetype2 -I/usr/local/include/pixman-1 -I/usr/local/include/gtk-unix-print-2.0 -I/usr/local/include -I/usr/local/include -DMOZILLA_CLIENT -include ../../mozilla-config.h nsBlockFrame.cpp In file included from ../../dist/include/content/nsContentUtils.h:46, from ./../../content/base/src/nsGenericElement.h:59, from ./../../content/base/src/nsStyledElement.h:50, from ./../../content/base/src/nsMappedAttributeElement.h:48, from
./../../content/html/content/src/nsGenericHTMLElement.h:41, from nsBlockFrame.cpp:69: ../../dist/include/js/jsnum.h:150: warning: 'js_TraceRuntimeNumberState' initialized and declared 'extern' ../../dist/include/js/jsnum.h:150: error: variable or field 'js_TraceRuntimeNumberState' declared void ../../dist/include/js/jsnum.h:150: error: 'JSTracer' was not declared in this
scope ../../dist/include/js/jsnum.h:150: error: 'trc' was not declared in this scope nsBlockFrame.cpp: In member function 'PRBool nsBlockFrame::HandleOverflowPlaceholdersOnPulledLine(nsBlockReflowState&, nsLineBox*)': nsBlockFrame.cpp:4268: warning: unused variable 'taken' nsBlockFrame.cpp: In member function 'void nsBlockFrame::SetOverflowOutOfFlows(const nsFrameList&)': nsBlockFrame.cpp:4620: warning: unused variable 'result' nsBlockFrame.cpp: In member function 'virtual void nsBlockFrame::DeleteNextInFlowChild(nsPresContext*, nsIFrame*)': nsBlockFrame.cpp:5601: warning: unused variable 'prevInFlow' gmake[4]: *** [nsBlockFrame.o] Error 1 gmake[4]: Leaving directory
`/usr/ports/www/firefox3/work/mozilla/layout/generic' gmake[3]: *** [libs] Error 2 gmake[3]: Leaving directory `/usr/ports/www/firefox3/work/mozilla/layout' gmake[2]: *** [libs_tier_gecko] Error 2 gmake[2]: Leaving directory `/usr/ports/www/firefox3/work/mozilla' gmake[1]: *** [tier_gecko] Error 2 gmake[1]: Leaving directory `/usr/ports/www/firefox3/work/mozilla' gmake: *** [default] Error 2 *** Error code 2

Stop in /usr/ports/www/firefox3. ** Command failed [exit code 1]: /usr/bin/script -qa /tmp/portupgrade.39797.0 env UPGRADE_TOOL=portupgrade UPGRADE_PORT=firefox-2.0.0.14_1,1 UPGRADE_PORT_VER=2.0.0.14_1,1 make BATCH=yes WITH_OPENSSL_PORT=yes WITH_OPENSSL=yes WITHOUT_GNOME=esound WITHOUT_CUPS=yes WITH_BDB_VER=46 WITH_MYSQL_VER=50 WITH_OPTIMIZED_CFLAGS=yes WITH_SMB=yes
DISABLE_VULNERABILITIES=yes ** Fix the problem and try again. ** Listing the failed packages (-:ignored / *:skipped / !:failed) ! www/firefox3 (firefox-2.0.0.14_1,1) (new compiler error)