Upgrade to Ubuntu 18.04. Compilation error. Make a backup.
The error message is as follows
FAILED: /bin/bash -c "prebuilts/misc/linux-x86/flex/flex-2.5.39 -oout/target/product/bullhead/obj/STATIC_LIBRARIES/libedify_intermediates/lexer.cpp bootable/recovery/edify/lexer.ll"
flex-2.5.39: loadlocale.c:130:_nl_intern_locale_data: ??'cnt < (sizeof (_nl_value_type_LC_TIME)/sizeof (_nl_value_type_LC_TIME[0]))' ???
Aborted (core dumped)
Solution:
Adding export LC_ALL=C
before compiling will solve the problem.