blind fix for double declarations

https://github.com/curl/curl/actions/runs/10801770763/job/29962562524?pr=14772#step:22:16

tests/mk-bundle-server.pl

@@ -39,6 +39,7 @@ foreach my $src (@ARGV) {
 print <<HEADER
 /* !checksrc! disable COPYRIGHT all */
 
+#define MEMDEBUG_NODEFINES
 #include "first.h"
 HEADER
     ;

tests/server/first.c

@@ -25,6 +25,11 @@
 #include <string.h>
 #include "first.h"
 
+#ifdef CURLDEBUG
+#  define MEMDEBUG_NODEFINES
+#  include "memdebug.h"
+#endif
+
 int main(int argc, char **argv)
 {
   main_func_t main_func;