dbghelp: All parameters of MiniDumpReadDumpStream() except base are optional.

[Dmitry Timoshkov]

This patch eliminates the iedw.exe (IE7 crash detector) crash. I confirmed
that this patch is correct with modified samples from debuginfo.com.
---
 dlls/dbghelp/minidump.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/dlls/dbghelp/minidump.c b/dlls/dbghelp/minidump.c
index 78e754f..6bc8070 100644
--- a/dlls/dbghelp/minidump.c
+++ b/dlls/dbghelp/minidump.c
@@ -1005,9 +1005,9 @@ BOOL WINAPI MiniDumpReadDumpStream(PVOID base, ULONG str_idx,
         {
             if (dir->StreamType == str_idx)
             {
-                *pdir = dir;
-                *stream = (char*)base + dir->Location.Rva;
-                *size = dir->Location.DataSize;
+                if (pdir) *pdir = dir;
+                if (stream) *stream = (char*)base + dir->Location.Rva;
+                if (size) *size = dir->Location.DataSize;
                 return TRUE;
             }
         }
-- 
1.6.2.4