Stub implementation for MsiGetFileHashA/W.

diff --git a/include/msi.h b/include/msi.h
index 862bd04..1c63f18 100644
--- a/include/msi.h
+++ b/include/msi.h
@@ -183,6 +183,11 @@
     MSICODE_PATCH = 0x40000000L
 } MSICODE;
 
+typedef struct _MSIFILEHASHINFO {
+    ULONG dwFileHashInfoSize;
+    ULONG dwData[4];
+} MSIFILEHASHINFO, *PMSIFILEHASHINFO;
+
 #define MAX_FEATURE_CHARS 38
 
 /* Strings defined in msi.h */
@@ -531,6 +536,10 @@
 UINT WINAPI MsiEnumPatchesW(LPCWSTR, DWORD, LPWSTR, LPWSTR, DWORD*);
 #define     MsiEnumPatches WINELIB_NAME_AW(MsiEnumPatches)
 
+UINT WINAPI MsiGetFileHashA(LPCSTR, DWORD, PMSIFILEHASHINFO);
+UINT WINAPI MsiGetFileHashW(LPCWSTR, DWORD, PMSIFILEHASHINFO);
+#define     MsiGetFileHash WINELIB_NAME_AW(MsiGetFileHash)
+
 /* Non Unicode */
 UINT WINAPI MsiCloseHandle(MSIHANDLE);
 UINT WINAPI MsiCloseAllHandles(void);