RE: Updating top-level autoconf to 2.59

["Dave Korn" <dave dot korn at artimi dot com>]

On 09 February 2007 08:34, Erik Christiansen wrote:

  Unless I've really misunderstood what you're trying to say here, ...

> --build seems to be a synonym for --host, 

  ... a false premise like this ...

> so its only useful purpose
> that I've imagined so far is to specify a native build if configure
> fails to detect that to the user's satisfaction.

  ... leads inevitably to a false conclusion.

  The build machine is the one that you are building your (cross-)compiler on.
The host is the one that the completed (cross-)compiler will *run* on.

  If build!=host, this means you are building a compiler that will not run on
the box you are compiling it on, i.e. you are cross-compiling a compiler.

  If then host!=target, that means that the compiler you are cross-compiling
is itself a cross-compiler; if host==target, it means the compiler you are
cross-compiling is a native compiler.

  If build==host, you are compiling a native executable that will run on the
same machine you are building it on, i.e. you are /not/ cross-compiling, just
compiling.  Whether or not the thing you are compiling turns out to be a
compiler or a cross-compiler depends on whether host==target or not; if it
does, then all three are the same and you just built a native compiler, if
not, then you just compiled a cross-compiler.

  I don't therefore understand why you say that build and host are synonymous;
they play different semantic roles in specifying both the nature of the
compilation that is taking place and the nature of the compiler that will be
generated.


    cheers,
      DaveK
-- 
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