Portable Makefiles (was: I need support with a planned POSIX make extension)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> In other words: := cannot appear in portable makefiles.
As someone writing a lot of (private) stuff in bmake, I'm wondering what 
a portable makefile in this context is.
Apart from auto-generated stuff, my impression is you can't write anything 
non-trivial in portable make languge as it lacks most basic things like 
conditionals or loops (not to speak of bmake's wonderful world of stackable 
variable modifiers).
So there must be some application of the operators discussed in auto-generated 
makefiles that I'm missing.