differences between gmake and freebsd's make

[Harlan Stenn]

I've got a project that uses automake-1.9.6.

I run autoreconf.  I go to a FreeBSD machine, create a subdir for the
build, cd there, and run ../configure.

I run 'gmake' and everything builds.

I run 'gmake' again and the beast completes without building anything
(no surprise).

I run 'make' and things get built.

I understand this is a vague report.  Before I get down and dirty to
figure out exactly what files/dependencies are causing this, does this
ring any bells for anybody and has this been discussed/evaluated before?

H