build: OK, maybe 32-bit machines could work

I accidentally did a pre-push verification on a 32-bit build host.
There were a surprisingly small number of problems, so fix them.

Bees now builds on a 32-bit host.  Let's not update README just yet,
though:  the 32-bit ioctl support fails immediately after startup on a
64-bit kernel.

lib/fs.cc

@@ -834,7 +834,7 @@ namespace crucible {
 	}
 
 	string
-	btrfs_search_objectid_ntoa(unsigned objectid)
+	btrfs_search_objectid_ntoa(uint64_t objectid)
 	{
 		static const bits_ntoa_table table[] = {
 			NTOA_TABLE_ENTRY_ENUM(BTRFS_ROOT_TREE_OBJECTID),

lib/ntoa.cc

@@ -7,7 +7,7 @@
 namespace crucible {
 	using namespace std;
 
-	string bits_ntoa(unsigned long n, const bits_ntoa_table *table)
+	string bits_ntoa(unsigned long long n, const bits_ntoa_table *table)
 	{
 		string out;
 		while (n && table->a) {