ncurses 5.7 - patch 20100424

+ fix some strict compiler warnings in ncurses library.
+ modify configure macro CF_HEADER_PATH to not look for variations in
  the predefined include directories.
+ improve configure macros CF_GCC_VERSION and CF_GCC_WARNINGS to work
  with gcc 4.x's c89 alias, which gives warning messages for cases
  where older versions would produce an error.