MFC r289477:

MFC r289477:

  Fix a strange macro re-definition compile error.  If the VM_MAXUSER_ADDRESS
  value is defined as a config option the definition is emitted into
  opt_global.h which is force-included into everything.  In addition, the
  symbol is emitted by the genassym mechanism, but that by its nature reduces
  the value to a 0xnnnnnnnn number.  When compiling a .S file you end up
  with two different definitions of the macro (they evaluate to the same
  number, but the text is different, upsetting the compiler).

git-svn-id: svn://svn.freebsd.org/base/stable/10@294690 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f