twain32shim: Windows directory might not be in DLL search path sometimes

So try the full path to TWAIN_32.DLL if first try failed.

Change-Id: I9ad262c91ebc7b3df63fbec3ffe34595ffd78c75
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/103669
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

extensions/Executable_twain32shim.mk

@@ -37,6 +37,7 @@ $(eval $(call gb_Executable_add_exception_objects,twain32shim,\
 ))
 
 $(eval $(call gb_Executable_use_system_win32_libs,twain32shim,\
+    Ole32 \
     shell32 \
 ))
 

extensions/source/scanner/twain32shim.cxx

@@ -254,7 +254,20 @@ void ImpTwain::ImplOpenSourceManager()
 {
     if (TWAINState::DSMunloaded == m_nCurState)
     {
-        if ((m_hMod = LoadLibraryW(L"TWAIN_32.DLL")))
+        m_hMod = LoadLibraryW(L"TWAIN_32.DLL");
+        if (!m_hMod)
+        {
+            // Windows directory might not be in DLL search path sometimes, so try the full path
+            PWSTR sPath;
+            if (SUCCEEDED(SHGetKnownFolderPath(FOLDERID_Windows, 0, nullptr, &sPath)))
+            {
+                std::wstring sPathAndFile = sPath;
+                CoTaskMemFree(sPath);
+                sPathAndFile += L"\\TWAIN_32.DLL";
+                m_hMod = LoadLibraryW(sPathAndFile.c_str());
+            }
+        }
+        if (m_hMod)
         {
             m_nCurState = TWAINState::DSMloaded;
 

extensions/source/scanner/twain32shim.hxx

@@ -11,6 +11,7 @@
 #pragma once
 
 #include <prewin.h>
+#include <Shlobj.h>
 #include <postwin.h>
 #include <exception>
 #include <string>