Fixes for function prototypes without arguments.

diff --git a/include/dbghelp.h b/include/dbghelp.h
index f18f2a0..8ec5f93 100644
--- a/include/dbghelp.h
+++ b/include/dbghelp.h
@@ -895,7 +895,7 @@
 typedef BOOL     (WINAPI* PSYMBOLSERVERCLOSEPROC)(void);
 typedef BOOL     (WINAPI* PSYMBOLSERVERSETOPTIONSPROC)(UINT_PTR, ULONG64);
 typedef BOOL     (CALLBACK* PSYMBOLSERVERCALLBACKPROC)(UINT_PTR, ULONG64, ULONG64);
-typedef UINT_PTR (WINAPI* PSYMBOLSERVERGETOPTIONSPROC)();
+typedef UINT_PTR (WINAPI* PSYMBOLSERVERGETOPTIONSPROC)(void);
 typedef BOOL     (WINAPI* PSYMBOLSERVERPINGPROC)(LPCSTR);
 
 #define SSRVOPT_CALLBACK            0x0001