build: squashed commit of Linaro patches

http://android.git.linaro.org/gitweb/platform/build.git/commit/69b2ce2227e8bd8d07beb936bffb9a73dc41c755
http://android.git.linaro.org/gitweb/platform/build.git/commit/aa9236ac35a17ef31b9fc7e449992d789e21a55c
http://android.git.linaro.org/gitweb/platform/build.git/commit/1c69db53b5827116c2eedba46568d08770468e14
http://android.git.linaro.org/gitweb/platform/build.git/commit/d9567ee90dcaa78613cdbea1315f9913771a3687
http://android.git.linaro.org/gitweb/platform/build.git/commit/479148e18389b467bb6ed59ba641f44ebdd38440
http://android.git.linaro.org/gitweb/platform/build.git/commit/f35c4bdf8adc5e8622151e49208d82f28c6d6fd1
http://android.git.linaro.org/gitweb/platform/build.git/commit/b18813b29b9462ec54b2635e94e441a0e52b8d5f
http://android.git.linaro.org/gitweb/platform/build.git/commit/6015e525375d41e503f40c459d2dfdfdb5247fa2
http://android.git.linaro.org/gitweb/platform/build.git/commit/775e22f38d62d9ba09af2cdd422a7ea64806a556
http://android.git.linaro.org/gitweb/platform/build.git/commit/ed61530e0978f7bfb92255b925ae7b5471f3b7c6

NOTICE: These commits had to be applied 'manually', since Linaro seems
        to have some serious problems with their GIT.
        For example, at the time of this commit, refs/heads/master
        could be fetched, but refs/heads/linaro_android_4.4.2 would
        fail because of missing objects on the remote ref.

Change-Id: Ib98075149de8d17d6a8356790de7e068c0973dc6
LDFLAGS: switch to -O2, -Wl,--sort-common -s

references:
http://forums.gentoo.org/viewtopic.php?t=67777
https://mail.gnome.org/archives/desktop-devel-list/2004-September/msg00377.html
http://www.akkadia.org/drepper/dsohowto.pdf

Thanks to VanirAOSP!
https://github.com/VanirAOSP/build/commit/af4089fe95d3c25b045c9c12fd634e3c6a74c71b

Change-Id: I7e464d51b1b98cb803b0d00ab84f1752892b566a
build: optionally use the system's ccache

ccache 3.x supports direct mode
(http://ccache.samba.org/manual.html#_the_direct_mode)
This is not supported in the prebuilt version. Direct mode has been
shown to decrease build time by up to 40x, compared to preprocessor mode
used in ccache 2.4, which is substantially less

Thanks to VanirAOSP!
https://github.com/VanirAOSP/build/commit/e802113de5ca54b926c6a7a32b231d10e3a0807a

Change-Id: I6a930eca9244f450c69bc2ca170fc6582f487fc4
build: define optimization level via eos_config.mk

Change-Id: I703136906cc31ae0ed1aa865b6fdfa85d948d830
build: disable strict-aliasing by default

Change-Id: I4aa8684a3f9c80ffcf01e4028b6b5ef0b23c594e