suricata: guard RLIMIT_NPROC usage

Only use RLIMIT_NPROC when the platform exposes that resource limit constant.

src/suricata.c

@@ -3225,7 +3225,7 @@ void SuricataPostInit(void)
 #endif
 
     if (limit_nproc) {
-#if defined(HAVE_SYS_RESOURCE_H)
+#if defined(HAVE_SYS_RESOURCE_H) && defined(RLIMIT_NPROC)
 #ifdef linux
         if (geteuid() == 0) {
             SCLogWarning("setrlimit has no effect when running as root.");