If you try to do:

emerge-guado db

you end up with:
libtool: compile:  x86_64-cros-linux-gnu-gcc -B/usr/x86_64-pc-linux-gnu/x86_64-cros-linux-gnu/binutils-bin/2.25.51 -c -I. -I/build/guado/tmp/portage/sys-libs/db-4.7.25_p4-r5/work/db-4.7.25/build_unix/../dist/.. -D_GNU_SOURCE -D_REENTRANT -O2 -pipe -O2 -pipe -march=corei7 -g -fno-exceptions -fno-unwind-tables -fno-asynchronous-unwind-tables -clang-syntax /build/guado/tmp/portage/sys-libs/db-4.7.25_p4-r5/work/db-4.7.25/build_unix/../dist/../db_checkpoint/db_checkpoint.c  -fPIC -DPIC -o .libs/db_checkpoint.o
/build/guado/tmp/portage/sys-libs/db-4.7.25_p4-r5/work/db-4.7.25/build_unix/../dist/../rpc_server/c/db_server_proc.c:643:6: warning: assigning to 'u_int8_t *'
      (aka 'unsigned char *') from 'char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        gid = replyp->gid.gid_val;
            ^ ~~~~~~~~~~~~~~~~~~~
/build/guado/tmp/portage/sys-libs/db-4.7.25_p4-r5/work/db-4.7.25/build_unix/../dist/../cxx/cxx_env.cpp:589:5: error: cannot use 'throw' with exceptions disabled
                                throw dl_except;
                                ^


This is due to ChromeOS adding "-fno-exception" by default to CXX_FLAGS (I really can't think for the life of me why this makes any sense).

sys-libs/db is a dependency on net-proxy/squid, being added to the Pedra board, so this needs to be fixed.

One solution that works is calling cros_enable_cxx_exceptions on the ebuild.

I've tried to add a third_party/chromiumos-overlay/chromeos/config/env/sys-libs/db file that does the same, which seems to be the current solution for it, but it doesn't seem to do anything. Help?