- search for libdwarf.h in new locations (e.g., /usr/include/libdwarf/)
- build Bochs with -std=gnu++98 (gnu++14 is default since GCC 6.1)
- specify "proto2" syntax for protobuf messages
- minor build-system and C++ namespace fixes
Change-Id: I16dbc622c797ef8e936fe3c0fb9b03029d27529d