The dtmalloc provider uses the short description of a malloc type as the
function name of its corresponding DTrace probes. These descriptions may
contain whitespace, but probe names cannot, so just replace any whitespace
with underscores when creating probes.

MFC after:	1 week
 - Add a general purpose resource allocator, vmem, from NetBSD.  It was
   originally inspired by the Solaris vmem detailed in the proceedings
   of usenix 2001.  The NetBSD version was heavily refactored for bugs
   and simplicity.
 - Use this resource allocator to allocate the buffer and transient maps.
   Buffer cache defrags are reduced by 25% when used by filesystems with
   mixed block sizes.  Ultimately this may permit dynamic buffer cache
   sizing on low KVA machines.

Discussed with:	alc, kib, attilio
Tested by:	pho
Sponsored by:	EMC / Isilon Storage Division
Allow the PCI config address register to be read. The Linux
kernel does this. Also remove an unused header file.

Submitted by:	tycho nightingale at pluribusnetworks com
Reviewed by:	neel
Fix build.

Spotted by:	gjb