Fix definition of libengine_a_CPPFLAGS
Fix definition of libengine_a_CPPFLAGS

We are only supposed to extend this variable by adding the flags for Lutok,
not redefine it altogether.

This change was r246 in Subversion.

jmmv/kyua,rodrigc/kyua,jmmv/kyua,jmmv/kyua,rodrigc/kyua,rodrigc/kyua,rodrigc/kyua,jmmv/kyua