Should build-sysroot be considered for setting inhibit_libc?

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Should build-sysroot be considered for setting ...
\ Stephen M. Kenton (11 Oct 2007)
. \ Dan Kegel (13 Oct 2007)

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Subject:	Should build-sysroot be considered for setting inhibit_libc?
Group:	Gcc
From:	Stephen M. Kenton
Date:	11 Oct 2007

I'm working on a patch to the top level configure to detect if inhibit_libc
will set for gcc and to avoid trying to build certain libraries in that
case.
I started to just clone the inhibit_libc logic from the gcc/configure,
but as
Ian commented, it is a bit strange. Then I realized that build-sysroot
is not
checked at all. Under what conditions should inhibit_libc really be set?
Extending the current logic would result in this, is it what is really
wanted?

1. Cross compiling with no build-sysroot, sysroot, or headers specified

2. Newlib is explicitly specified regardless of build-sysroot or sysroot
but without headers specified.

Should specifiying newlib in the absence of the newlib source continue
to be treated as meaning "force inhibit_libc" in some cases, or should
inhibit_libc just be exposed if that is desirable?

Steve Kenton