[isabelle-dev] Admin/PLATFORMS

[Makarius]

This is a summary of the multi-platform situation documented in
Admin/PLATFORMS of Isabelle/39cc38a06610:

  * Linux, Windows, Mac OS X are uniformly required to be 64bit
platforms; old 32bit Linux and Windows has been discontinued (32bit Mac
OS X has been discontinued by Apple long ago).

  * Linux, Windows, Mac OS X can always run native x86_64 executables,
although for Poly/ML this is still wasteful and avoided by if possible.
In contrast, the bundled JVM always runs on native x86_64.

  * Linux can run x86-linux executables only if suitable libraries are
installed (e.g. lib32stdc++6 on Ubuntu).

  * Windows can only run native x86-windows, but not x86-cygwin
executables; the POSIX emulation is exclusively x86_64-cygwin. This
still requires some updates of components (e.g. E prover, SPASS).

  * Mac OS X has now the base-line 10.10 Yosemite as testified by
macbroy31. 10.9 Mavericks has been discontinued: macbroy2 is now running
10.11 El Capitan and no longer suitable for building portable tools!


	Makarius