[build] Copy target CFLAGS into the host ones

We use host CFLAGS to build emugen, and it was missing all
flags one needs, including debug info and optimizations.

This CL copies the flags we use for target build.

+ Fix build errors after enabling Werror

Change-Id: I6be85210f3e9e447fb603e48dace074296b59d0e
2 files changed
tree: a1341f520a549f84094fd82f41c5250fa168085a
  1. android/
  2. host/
  3. .gitignore