An intermediate "install" to the build dir is used with slibdir=/
causing install_names to be recorded for /libgcc_s.1.dylib, which are
obviously wrong.  Avoid this from happening by hard-assigning
shlib_slibdir with the correct value, such that even though the library
is installed into the build dir (offsetted at /), it's install_name is
still set to something which is correct afterwards.

--- gcc-4.4.1/libgcc/Makefile.in
+++ gcc-4.4.1/libgcc/Makefile.in
@@ -31,7 +31,7 @@
 
 exec_prefix = @exec_prefix@
 libdir = @libdir@
-shlib_slibdir = @slibdir@
+shlib_slibdir = $(libdir)/gcc/$(host_noncanonical)/$(version)
 
 SHELL = @SHELL@