Fixes in 2000/primenum - int main from void main

To make the entry more portable the void main was changed to int main.

The no arg check was NOT fixed: this is a documented feature not a bug
and should not be fixed. If one wants to fix it for personal enjoyment
(if they can get pleasure from a couple seconds :-) ) they may do so but
it is not to be committed.

2000/primenum/primenum.c

@@ -1,8 +1,8 @@
-#define BeginProgram void main(int argc, char *argv[])
+#define BeginProgram int main(int argc, char *argv[])
 #define CloseBrace }
 #define CommandLineArgument -1
 #define Declare int i,j,n,Flag=1;
-#define EndOfProgram return;
+#define EndOfProgram return 0;
 #define False 0;
 #define ForLoop ;for
 #define GetCommandLineArgument n=atoi(argv[1]);