upgrading Solaris 2.5.1 to 2.6

[Jeffrey A Law]

  In message < 199802061207.NAA11809@broceliande.shfj.cea.fr >you write:
  > As you can see in the example below, gcc replaces some files in
  > 	/usr/include/sys
  > with its own files. So my questions are:
  > - Do I have to configure and install the compiler once again
  >   every time we upgrade the system?
Yes.  It's unfortunate, but necessary.

  > - Why replace the original system header files?
Because there are problems with them that will be exposed by gcc or g++.

  > - Is there some way to achieve portability between minor OS
  >   versions?
Not as long as the vendors keep changing their include files.

jeff