general - <Apache>error when compiling CPP modules

Hi,

I am working on Linux Platform. I am just trying to port a CPP module to apache as a module. When I try to build the Apache , it throws an error as follows

libtool: unrecognized option `-DLINUX=2'

Later I did some search and changed the config_vars.mk file under the "build" directory of Apache.
The line that I changed is as follows
Before :EXTRA_CPPFLAGS = -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE
Changed to : EXTRA_CPPFLAGS = -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE

So I just removed the option from EXTRA_CPPFLAG and it worked fine.
I did this just to overcome the error ..

Can anyone please let me know wht is the correct way of compiling the CPP module and provide some description. The C modules compiles fine.

Thanks