Comment 122 for bug 908508

Created attachment 619876
Use YARR interpreter instead of PCRE on platforms where YARR JIT is not supported

Fwiw here's the (simpler) patch i'm working on (no, i didn't gave up..) :
- it doesnt touch the ENABLE_ASSEMBLER hell -> shouldnt affect tier1 archs
- it uses the dummy empty cacheFlush implem for PPC in ExecutableAllocator.h
- adds ExecutableAllocator.cpp/ExecutableAllocatorPosix.cpp to CPPSRCS in !YARR_JIT case (i didnt do the ifdef WIN/OS2 dance, as i doubt win/os2 might fall in the !YARR_JIT case someday.. prove me wrong :)
- inconditionally includes ExecutableAllocator.h in wtfbridge.h so that the definition of ExecutableAllocator class is available everywhere

It currently builds a working shell on ppc (regress tests passes except testConservativeGC but that seems related to #750620), i've yet to confirm it produces a working firefox. I'll also see if it fixes the build on sparc64, and then i'll send it to try to see if it breaks anything else.