since a memory page's size may vary on various architectures and kernel
 configurations.

Will use getpagesize() if it exists, the PAGE_SIZE #define from older kernels
 if that doesn't, and #error out if that's not there either...but it's
 probably 4096 in that case. We may revisit this.

   Fixes Bugzilla #392.

--HG--
branch : SDL-1.2
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/branches/SDL-1.2%402273