win32: pcapif: ensure we can run with npcap as well

By default, npcap keeps its DLLs not in system32 but in system32/npcap.
To load DLLs from there, mark them as "delay load DLLs" and adjust the
DLL search path before using/loading them.

Signed-off-by: Simon Goldschmidt <goldsimon@gmx.de>

contrib/ports/win32/pcapif_helper.h

@@ -22,6 +22,8 @@ void pcapifh_linkstate_close(struct pcapifh_linkstate* state);
 void *pcapifh_alloc_readonly_copy(void *data, size_t len);
 void pcapifh_free_readonly_mem(void *data);
 
+void pcapifh_init_npcap(void);
+
 #ifdef __cplusplus
 }
 #endif