[cvs-nhc98] patch applied (cpphs): Move parsing of #include filename into CppIfdef

[Malcolm Wallace]

Tue Jun  5 02:38:41 PDT 2007  Malcolm.Wallace at cs.york.ac.uk
  * Move parsing of #include filename into CppIfdef
  This allows proper treatment of recursive text expansion and
  parameterised macro-calls in the filename itself.

    M ./Language/Preprocessor/Cpphs/CppIfdef.hs -2 +11
    M ./Language/Preprocessor/Cpphs/ReadFirst.hs -19 +4