Include all library files when building fat library

[zhuhaow]

Currently, the script only combines libraries provided in --boost-libs, by iterating for NAME in $BOOTSTRAP_LIBS; do.

However, boost binary has dependencies, e.g, if I build log, then here is what are actually built (by default), log library and all its dependencies.

libboost_atomic.a
libboost_chrono.a         
libboost_date_time.a      
libboost_filesystem.a     
libboost_log.a           
libboost_log_setup.a      
libboost_regex.a          
libboost_system.a         
libboost_thread.a

The outputted libboost.a, however, only consists of libboost_log.a.

Sometimes, this can be worked around by also providing the list of dependencies in --boost-libs, but libboost_log_setup.a is not a standalone library, so this won't work.

Why not just take all .a files in stage folder as target library files?

[faithfracture]

That's a great idea!