removing spaces from concatenated variables

[Dan DeJohn]

I need to construct a UNIX path from some variables and I don't know how 
to get rid of the space that make puts between the variables when 
concatenating them. I need a $(strip) function that will remove the 
internal spaces as well as the leading and trailing ones.

FOO := foo
BAR := bar

PATH := $(FOO):$(BAR)

I'm using GNU Make version 3.79.1.

Thanks,
Dan