executing make in a different directory from a Makefile

[Ravi Parimi]

I have a directory structure like this:

/opt/src/main/ ------> build/
                     ------> tests/
There is one makefile each in the build/ and tests/ directories. I am
trying to invoke the
make in build/ from the makefile in tests/ by adding a new target in
tests/Makefile:

main:
          cd ../build;make PRODUCT=server OBJDIR=obj host

The problem with the above is that none of the variables in
build/Makefile are getting set when this command is executed. Is there
a way to fix this problem?

Many thanks!