Use extern for __seed__ (#2 #8)

Author: gkobeaga

src/cmd/opt.c

@@ -4,6 +4,8 @@
 #include "cp/heur/ea/ea.h"
 #include <sys/stat.h>
 
+unsigned long __seed__;
+
 struct cmd_args
 {
     const char *data_file;

src/op-solver.h

@@ -57,7 +57,7 @@ extern "C"
 #define SOLVER_VERBOSITY_INFO 2
 #define SOLVER_VERBOSITY_DEBUG 3
 
-    unsigned long __seed__;
+    extern unsigned long __seed__;
 
 #ifndef SOLVER_MAXINT
 #define SOLVER_MAXINT ((int)(~(((unsigned)1) << ((8 * sizeof(int)) - 1))))