with FEATURES="ccache distcc" firefox build ignores ccache, but uses distcc. With FEATURES="ccache" only ccache is used. Other packages use both ccache and distcc without problems. Mine ccache is 3.1.7 and distcc is 3.2_rc1.
Sample of ps ax | grep gcc output:
11229 pts/7 SN+ 0:00 /usr/lib/distcc/bin/i686-pc-linux-gnu-g++ -o nsHttpHandler.i_o -c -I../../../dist/stl_wrappers -I../../../dist/syste
m_wrappers -include /var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/config/gcc_hidden.h -DMOZILLA_INTERNAL_API -D_IMPL_NS_COM
-DEXPORT_XPT_API -DEXPORT_XPTC_API -D_IMPL_NS_GFX -D_IMPL_NS_WIDGET -DIMPL_XREAPI -DIMPL_NS_NET -DIMPL_THEBES -DSTATIC_EXPORTABLE_JS_API -DOSTYPE="Linux3.3" -DOSARCH=Linux -DEXCLUDE_SKIA_DEPENDENCIES -DOS_LINUX=1 -DOS_POSIX=1 -DIMPL_NS_NET -I/var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/netwerk/protocol/http/../../base/src -I/var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/xpcom/ds -I/var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/content/base/src -I/var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/content/events/src -I/var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/ipc/chromium/src -I/var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/ipc/glue -I../../../ipc/ipdl/_ipdlheaders -I/var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/netwerk/protocol/http -I. -I../../../dist/include -I../../../dist/include/nsprpub -I/usr/include/nspr -I/usr/include/nss -fPIC -fno-rtti -Wall -Wpointer-arith -Woverloaded-virtual -Wsynth -Wno-ctor-dtor-privacy -Wno-non-virtual-dtor -Wcast-align -Wno-invalid-offsetof -Wno-variadic-macros -Werror=return-type -march=athlon-xp -m32 -funswitch-loops -fpredictive-commoning -fgcse-after-reload -ftree-vectorize -mstackrealign -ftree-loop-linear -ftree-loop-im -fweb -frename-registers -mfpmath=sse -pipe -mno-avx -fno-exceptions -fno-strict-aliasing -std=gnu++0x -pthread -ffunction-sections -fdata-sections -pipe -DNDEBUG -DTRIMMED -g -fprofile-generate -O2 -fomit-frame-pointer -DMOZILLA_CLIENT -include ../../../mozilla-config.h -MD -MF .deps/nsHttpHandler.pp /var/tmp/portage/www-client/firefox-12.0-r2/work/mozilla-release/netwerk/protocol/http/nsHttpHandler.cpp
Created attachment 313507 [details]
Created attachment 313509 [details]
PATH looks OK, maybe firefox build tools strip it somehow.
Please attach the entire build log to this bug report.
Judging from my build logs, it appears to figure a couple of things out wrongly in src_configure() (it appears to ignore CHOST), and your ps output doesn't suggest that it isn't using ccache or distcc, just that there is a subprocess that does not include that path. So you may have found a genuine bug but without a build log, we cannot be certain.
I noticed that ccache is not used when rebuild of the same version of firefox took too long time and ccache -s showed no changes in counters.
I'm uploading full build log (compressed, too large otherwise) and environment of the new build.
Created attachment 313621 [details]
Created attachment 313623 [details]
Nothing for toolchain to do here.
The problem is still here with firefox-20.0.1.
I undestand what is happening: ccache doesn't support profile-related options, -fprofile-generate in particular and ccache's counter of "unsupported compiler option" is growing during firefox build.