Pass C/CXX ABI info to subprojects from top-level configuration.
Pass C/CXX ABI info to subprojects from top-level configuration.

Speeds up the build slightly, because it doesn't have to be recalculated in every subproject.  Also helps avoid #121 because the top-level project is less likely to run into the long-path problem while compiling the ABI test.

Closes #122.

lucmichalski/hunter,stohrendorf/hunter,daminetreg/hunter,mchiasson/hunter,fire-hunter/hunter,tatraian/hunter,sumedhghaisas/hunter,madmongo1/hunter,Knitschi/hunter,ErniBrown/hunter,alamaison/hunter,mchiasson/hunter,ledocc/hunter,akalsi87/hunter,daminetreg/hunter,lucmichalski/hunter,caseymcc/hunter,xsacha/hunter,dmpriso/hunter,isaachier/hunter,dvirtz/hunter,daminetreg/hunter,NeroBurner/hunter,xsacha/hunter,pretyman/hunter,ThomasFeher/hunter,NeroBurner/hunter,stohrendorf/hunter,sumedhghaisas/hunter,dmpriso/hunter,lucmichalski/hunter,vdsrd/hunter,shekharhimanshu/hunter,zhuhaow/hunter,ErniBrown/hunter,jkhoogland/hunter,jkhoogland/hunter,x10mind/hunter,stohrendorf/hunter,tatraian/hunter,RomanYudintsev/hunter,ThomasFeher/hunter,zhuhaow/hunter,Knitschi/hunter,pretyman/hunter,designerror/hunter,fwinnen/hunter,dan-42/hunter,designerror/hunter,akalsi87/hunter,dmpriso/hunter,jkhoogland/hunter,zhuhaow/hunter,madmongo1/hunter,caseymcc/hunter,pretyman/hunter,madmongo1/hunter,NeroBurner/hunter,ledocc/hunter,ruslo/hunter,dvirtz/hunter,ulricheck/hunter,fire-hunter/hunter,dvirtz/hunter,mchiasson/hunter,headupinclouds/hunter,ikliashchou/hunter,ThomasFeher/hunter,shekharhimanshu/hunter,fire-hunter/hunter,ingenue/hunter,RomanYudintsev/hunter,sumedhghaisas/hunter,pretyman/hunter,ingenue/hunter,RomanYudintsev/hunter,ikliashchou/hunter,akalsi87/hunter,ruslo/hunter,vdsrd/hunter,ikliashchou/hunter,ruslo/hunter,fwinnen/hunter,headupinclouds/hunter,NeroBurner/hunter,tatraian/hunter,ingenue/hunter,alamaison/hunter,isaachier/hunter,ulricheck/hunter,dan-42/hunter,ulricheck/hunter,isaachier/hunter,vdsrd/hunter,madmongo1/hunter,ruslo/hunter,designerror/hunter,mchiasson/hunter,shekharhimanshu/hunter,caseymcc/hunter,x10mind/hunter,ErniBrown/hunter,ikliashchou/hunter,dan-42/hunter,xsacha/hunter,isaachier/hunter,ErniBrown/hunter,xsacha/hunter,ledocc/hunter,x10mind/hunter,Knitschi/hunter,dan-42/hunter,fwinnen/hunter,headupinclouds/hunter,ingenue/hunter,alamaison/hunter