Add a fragmentation fallback in ggc-page v2

Add a fragmentation fallback in ggc-page v2

There were some concerns that the earlier munmap patch could lead
to address space being freed that cannot be allocated again
by ggc due to fragmentation. This patch adds a fragmentation
fallback to solve this: when a GGC_QUIRE_SIZE sized allocation fails,
try again with a page sized allocation.

Passes bootstrap and testing on x86_64-linux with the fallback
forced artificially.

v2: fix missed initialization bug added in last minute edit.

gcc/:
2011-10-20  Andi Kleen  <ak@linux.intel.com>

	* ggc-page (alloc_anon): Add check argument.
	(alloc_page): Add fallback to 1 page allocation.
	Adjust alloc_anon calls to new argument.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@180649 138bc75d-0d04-0410-961f-82ee72b054a4