[PATCH] Remove hard-coded path to /usr/bin/libtool for Darwin

[Shantonu Sen <ssen at opendarwin dot org>]

gcc/config/darwin.h has:

 #define LINK_COMMAND_SPEC "\
 %{!fdump=*:%{!fsyntax-only:%{!precomp:%{!c:%{!M:%{!MM:%{!E:%{!S:\
    %{!Zdynamiclib:%(linker)}%{Zdynamiclib:/usr/bin/libtool} \

Note the explicit path to Darwin libtool. For people not familiar with  
Darwin, this is an Apple tool used to create shared and static  
libraries, not GNU libtool.

Not only does this violate the documentation on searching for target  
tools (tools directory, then OS-specific dirs, then PATH), it creates  
the following issues:

1) Cross compilers (for instance Linux hosted, targetting Darwin) by  
default do the wrong thing, since /usr/bin/libtool is often GNU  
libtool. Even if you use odcctools (<http://www.opendarwin.org/projects/odcctools/ 
>), the other target tools like "as" and "ld" are found, but  
"libtool" stubbornly isn't without source tree modification

2) Even for a native Darwin bootstrap, the stock toolchain from Apple  
may have bugs which are fixed in a local install of odcctools built  
with --prefix=/usr/local/foo. gcc's configure process generally finds  
the new tools, but for the same reasons as above, the stock /usr/bin/ 
libtool is used, which can result in incorrect behavior when mixed and  
matched with object files created by /usr/local/foo/bin/as

This partially addresses
PR 24598 - Need to support odcctools and its ablity to use --prefix  
and libtool

However I would not consider this fixed, because my changes only  
facilitate finding these tools if they are already in your PATH.  
Another common desire is for functionality on par with --with-as/-- 
with-ld. There is no --with-darwin-libtool, and its existence is  
Darwin specific. Until there's a good way of doing that so that  
odcctools doesn't have to be in your PATH in order for the right tools  
to be invoked, that bug should remain open.

Some may be concerned by "what if you have GNU libtool in your PATH  
and it gets used instead?". Apple for this reason installs GNU libtool  
as "glibtool", and most people do the same to avoid conflicts in the  
bin namespace.

Regression tested on Mac OS X 10.4.4 (PowerPC) with the stock tools  
from Apple and no regressions.

The interesting part is when you have an in-development of odcctools  
and use it with mainline. Running the test suite with -m64 goes, for g+ 
+ for example, from:
                === g++ Summary ===

# of expected passes            9223
# of unexpected failures        1422
# of expected failures          63
# of unresolved testcases       77
# of unsupported tests          121
/Volumes/HD/ltmp/ssen/gcc-3-libtool-build/gcc/testsuite/g++/../../g++   
version 4.2.0 20060123 (experimental)

To:

                === g++ Summary ===

# of expected passes            11835
# of unexpected failures        53
# of expected failures          66
# of unsupported tests          121
/Volumes/HD/ltmp/ssen/gcc-4-odcctools-libtool-build/gcc/testsuite/g+ 
+/../../g++  version 4.2.0 20060123 (experimental)


Note that this change doesn't fix those testsuite problems, but rather  
it enables the fix in odcctools to be used by using the right versions  
of the tools to link things.

2006-01-23  Shantonu Sen  <ssen@opendarwin.org>

        * config/darwin.h (LINK_COMMAND_SPEC): Do not hardcode
        the path to Darwin libtool.


Index: config/darwin.h
===================================================================
--- config/darwin.h     (revision 110108)
+++ config/darwin.h     (working copy)
@@ -201,7 +201,7 @@
    linkers, and for positional arguments like libraries.  */
 #define LINK_COMMAND_SPEC "\
 %{!fdump=*:%{!fsyntax-only:%{!precomp:%{!c:%{!M:%{!MM:%{!E:%{!S:\
-    %{!Zdynamiclib:%(linker)}%{Zdynamiclib:/usr/bin/libtool} \
+    %{!Zdynamiclib:%(linker)}%{Zdynamiclib:libtool} \
     %l %X %{d} %{s} %{t} %{Z} \
     %{!Zdynamiclib:%{A} %{e*} %{m} %{N} %{n} %{r} %{u*} %{x} %{z}} \
     %{@:-o %f%u.out}%{!@:%{o*}%{!o:-o a.out}} \