newlib include directories during build

[Joel Sherrill <joel dot sherrill at OARcorp dot com>]

Hi,

I have locally noticed a build dependency problem with newlib
and other packages.  It is simple to fix but touches a handful
of things other than newlib.  I also think that I have found
a specific example of a more general problem -- packages that are
built "FOR A TARGET AND DEPEND ON THE C LIBRARY" have to be
aware of newlib.  Right now, there is too much to know to get
it right reliably.

This started when I noticed that the target libiberty has to know
more than I would think proper about newlib to be able to 
figure out what is supported.  There are complex rules in 
libiberty/configure.in to figure out what to build when using
newlib.  These should be unnecessary if my approach is followed.

Currently newlib builds a targ-include directory
during configure that does not contain the "portable" .h files
from newlib/include.  This requires that every package that
builds for the target has to know to look at targ-include AND
multiple directories within the newlib source.  See the 
stmp-targ-include stanza in newlib/Makefile.am for details.  
This stanza should also put the .h files under newlib/include 
in targ-include.

I discovered this because target-libiberty could not figure out what
was supported in newlib.  I started to add the path information and
realized that libiberty should not have to know about 
newlib/libc/machine and newlib/libc/sys/*.

My solution was pretty simple but is at such a level that I would
like some feedback.

====================================================================
Changes to newlib:

1.  Modify stmp-targ-include in newlib/Makefile.am to also install
the .h files in newlib/include

=====================================================================
Changes to libiberty:

NOTE:  Likely to apply to other packages built for the target that are 
dependent on the C Library.  This includes things like the C++
libraries.

1.  top level Makefile.in distributed with gcc currently has:

configure-target-libiberty: $(ALL_GCC)

Should be:

configure-target-libiberty: $(ALL_GCC) configure-target-newlib

2. libiberty needs to recognize that when "with newlib", cppflags
needs to have a -I for targ-include.  With this, it can figure out
what functionality is in newlib.

=====================================================================

GCC Issue:

I think that if newlib builds targ-include before gcc starts to build
target libraries, then "with newlib" can make sure .../target-include
is included in the target CPPFLAGS.  This should be enough to remove
the -Dinhibit_libc.

=====================================================================

I know this is a pretty far reaching report.  But it sure seems like
making targ-include complete would simplify things.

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel@OARcorp.com                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
   Support Available             (256) 722-9985