Made SCATTER_UNITS handle running out of valid spots better.

data/core/macros/utils.cfg

@@ -705,6 +705,17 @@
                 variable=possible_unit_locations
             [/store_locations]
 
+            [if]
+                [variable]
+                    name=possible_unit_locations.length
+                    less_than=1
+                [/variable]
+
+                [then]
+                    {VARIABLE units_to_place 0}
+                [/then]
+            [/if]
+
             {VARIABLE_OP unit_type_table_i add 1}
 
             [if]