Define scope macros with conditional @try/@autoreleasepool
Define scope macros with conditional @try/@autoreleasepool

Back the scope macros with @autoreleasepool for DEBUG builds, and @try
otherwise. This prevents suppressed return warnings in DEBUG, and otherwise
will prevent unnecessary autorelease pool allocations.

See jspahrsummers/libextobjc#51

sanojnambiar/libextobjc,liuruxian/libextobjc,WPDreamMelody/libextobjc,jiakai-lian/libextobjc,sunfei/libextobjc,bboyesc/libextobjc,telly/libextobjc,goodheart/libextobjc,sandyway/libextobjc,KBvsMJ/libextobjc