lguest: avoid shared libraries mapped over guest memory

Some versions of ld.so mmap the shared libraries right in over guest
memory, so compile lguest statically by default.

[ FC7 maps shared libraries very low, where the launcher maps guest's
  physical memory.  Quick fix is to link Launcher static, real fix is
  for 2.6.24. ]

-static is a simple fix. I expect this problem will be more common than we
like, as different distro's make different "improvements" to ld.so
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/lguest/Makefile

@@ -13,7 +13,9 @@ LGUEST_GUEST_TOP := ($(CONFIG_PAGE_OFFSET) - 0x08000000)
 
 CFLAGS:=-Wall -Wmissing-declarations -Wmissing-prototypes -O3 -Wl,-T,lguest.lds
 LDLIBS:=-lz
-
+# Removing this works for some versions of ld.so (eg. Ubuntu Feisty) and
+# not others (eg. FC7).
+LDFLAGS+=-static
 all: lguest.lds lguest
 
 # The linker script on x86 is so complex the only way of creating one