more noexcept to pleace GCC

* spot/bricks/brick-hashset (Row): Add noexcept.
* bin/autcross.cc (out_statistics): Likewise.
* bin/ltlcross.cc (statistics): Likewise.

bin/autcross.cc

@@ -345,7 +345,6 @@ struct in_statistics
 
 struct out_statistics
 {
-
   // If OK is false, output statistics are not available.
   bool ok;
   const char* status_str;
@@ -353,7 +352,7 @@ struct out_statistics
   double time;
   aut_statistics output;
 
-  out_statistics()
+  out_statistics() noexcept
     : ok(false),
       status_str(nullptr),
       status_code(0),

bin/ltlcross.cc

@@ -264,7 +264,7 @@ end_error()
 
 struct statistics
 {
-  statistics()
+  statistics() noexcept
     : ok(false),
       alternating(false),
       status_str(nullptr),

spot/bricks/brick-hashset

@@ -583,7 +583,7 @@ struct _ConcurrentHashSet : HashSetBase< Cell >
             return begin() + size();
         }
 
-        Row() : _data( nullptr ), _size( 0 ) {}
+        Row() noexcept : _data( nullptr ), _size( 0 ) {}
         ~Row() { free(); }
     };