* Reworked undefined symbol resolution in the runtime loader. Got rid of

the per-root-image breadth-first sorted image array. Instead we have a
  per-image hook function to resolve the symbols. The default function
  uses the sLoadedImages list directly, which is breadth-first sorted
  anyway. There's also a BeOS function for old-style symbol resolution
  and one for add-ons, which lacks a proper implementation yet (just
  uses old-style ATM).
* Made the dl*() functions POSIX compliant:
  - dlopen() does no longer use load_add_on(), but loads the object as a
    library. It also properly supports a NULL name, now -- the previous
    "_APP_" work-around did only work, if this soname was set on the
    program (unlikely for programs using this API).
  - Implemented RTLD_{GLOBAL,LOCAL}.
  - dlsym() looks up symbols properly now, i.e. not just in the given
    image, but breadth-first for an actual image or in load order for
    the global scope. It also supports the not-quite POSIX RTLD_DEFAULT
    and RTLD_NEXT extensions. Our RTLD_NEXT finds more symbols than in
    Linux (also in later dlopen()ed libraries), but that should be fine.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28568 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/posix/dlfcn.h

@@ -14,6 +14,11 @@
 #define RTLD_LOCAL	0	/* symbols are not available for relocating any other object */
 #define RTLD_GLOBAL	2	/* all symbols are available */
 
+/* not-yet-POSIX extensions (dlsym() handles) */
+#define RTLD_DEFAULT	((void*)0)
+	/* find the symbol in the global scope */
+#define RTLD_NEXT		((void*)-1L)
+	/* find the next definition of the symbol */
 
 #ifdef __cplusplus
 extern "C" {