unbreak build on OpenBSD due to undeclared identifier PATH_MAX
in version 5.3.0, there was a PATH_MAX defined for APPLE and OpenBSD
set to 255.
Re-add PATH_MAX define for OpenBSD, as it is defined in sys/syslimits.h
set to 1024
#include <openssl/hmac.h>
#include <openssl/cmac.h>
#if defined (__APPLE__) || defined(__OpenBSD__)
+#if defined(__OpenBSD__)
+#define PATH_MAX 1024 /* as defined in sys/syslimits.h */
+#endif
#include <libgen.h>
#include <sys/socket.h>
#else
