OpenBSD: Missing dlopen modes

[nphantasm]

RTLD_NODELETE and RTLD_NOLOAD are not defined for OpenBSD, although they are supported in its libc.

• RTLD_NODELETE documented in dlopen man page since OpenBSD 7.0
• RTLD_NOLOAD documented in dlopen man page since OpenBSD 7.2

From 7.9 headers:

$ grep RTLD /usr/include/dlfcn.h  
#define RTLD_LAZY       1
#define RTLD_NOW        2
#define RTLD_GLOBAL     0x100
#define RTLD_LOCAL      0x000
#define RTLD_TRACE      0x200
#define RTLD_NODELETE   0x400
#define RTLD_NOLOAD     0x800
#define RTLD_NEXT       ((void *) -1)   /* Search subsequent objects. */
#define RTLD_DEFAULT    ((void *) -2)   /* Use default search algorithm. */
#define RTLD_SELF       ((void *) -3)   /* Search the caller itself. */
#define DL_LAZY         RTLD_LAZY       /* Compat */

[tgross35]

Happy to take a PR here if you're up for it