8186115: libelf still referenced after 8172670
Reviewed-by: kvn, twisti, erikj, dholmes

8184338: switch minimum supported gcc version to 4.7
Reviewed-by: erikj, tbell

8179892: Update build documentation for JDK 9
Reviewed-by: erikj

8176509: Use pandoc for converting build readme to html
Reviewed-by: erikj