CXXFLAGS in automake 1.5

[Ted Irons]

I understand now the  significance of distinguishing
between user  and maintainer  env variables.

But  before automake 1.5 the following used to work in
the Makefile.am's; it no longer does.   Should it?

CXXFLAGS = @CXXFLAGS@  \
    -I$(top_srcdir)/src                  \
    $(K_CXXFLAGS)

Thanks in advance,
- Ted