qemu_memalign: Allow small alignments

The functions used by qemu_memalign() require an alignment that is at
least sizeof(void*). Adjust it if it is too small.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoît Canet <benoit@irqsave.net>

util/oslib-posix.c

@@ -88,6 +88,11 @@ void *qemu_oom_check(void *ptr)
 void *qemu_memalign(size_t alignment, size_t size)
 {
     void *ptr;
+
+    if (alignment < sizeof(void*)) {
+        alignment = sizeof(void*);
+    }
+
 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
     int ret;
     ret = posix_memalign(&ptr, alignment, size);