builtin include dir searches

[David Edelsohn]

>>>>> Phil Edwards writes:

Phil> Current CVS g++ does not search the g++-v3 include directory, which means
Phil> no C++ program using the standard headers can be compiled.  I would like
Phil> to fix this.  Where is the #include <...> search list built up?  I have
Phil> become miserably lost in the sources...

	The directory is determined by configure and substituted into
gcc_gxx_include_dir in the constructed gcc/Makefile.  include/g++-3 vs
include/g++ depends on whether one has configured for version-specific
libraries.  The "3" actually is a substituted value of ${libstdcxx_interface}

David