Improved support for on-target rules.

     * jamgram.yy: New nonterminal 'func'. Grammar now supports on-target
     	rule invocations inside '[' ']'.

svn path=/branches/perforce_2_4_merge/boost/tools/jam/; revision=13076
restored short-circuit evaluation

svn path=/branches/perforce_2_4_merge/boost/tools/build/; revision=13097
Tweaks.

    * compile.c (compile_while): Made it return a value, as in Perforce Jam.

svn path=/branches/perforce_2_4_merge/boost/tools/build/; revision=13109
Latest perforce changes integrated

svn path=/branches/perforce_2_4_merge/boost/tools/jam/; revision=13113
instantiation hacks for tru64cxx6.5

svn path=/branches/perforce_2_4_merge/boost/tools/build/; revision=13265