When loading the Python dll to run the postinstall script, try to load

it from the install directory (as reported by the registry) in case it
is not found on the default Loadlibrary search path.

Fixes SF 935091: bdist_winist post-install script fails on non-admin Python

Already backported.

PC/bdist_wininst/install.c

@@ -590,6 +590,22 @@ PyMethodDef meth[] = {
 	{"message_box", PyMessageBox, METH_VARARGS, NULL},
 };
 
+static HINSTANCE LoadPythonDll(char *fname)
+{
+	char fullpath[_MAX_PATH];
+	LONG size = sizeof(fullpath);
+	HINSTANCE h = LoadLibrary(fname);
+	if (h)
+		return h;
+	if (ERROR_SUCCESS != RegQueryValue(HKEY_CURRENT_USER,
+					   "SOFTWARE\\Python\\PythonCore\\2.3\\InstallPath",
+					   fullpath, &size))
+		return NULL;
+	strcat(fullpath, "\\");
+	strcat(fullpath, fname);
+	return LoadLibrary(fullpath);
+}
+
 static int prepare_script_environment(HINSTANCE hPython)
 {
 	PyObject *mod;
@@ -715,7 +731,7 @@ static int run_simple_script(char *script)
 	freopen(tempname, "a", stderr);
 	freopen(tempname, "a", stdout);
 
-	hPython = LoadLibrary (pythondll);
+	hPython = LoadPythonDll(pythondll);
 	if (!hPython) {
 		set_failure_reason("Can't load Python for pre-install script");
 		return -1;
@@ -1745,7 +1761,7 @@ InstallFilesDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 						"Compiling files to .pyc...");
 
 				SetDlgItemText(hDialog, IDC_INFO, "Loading python...");
-				hPython = LoadLibrary(pythondll);
+				hPython = LoadPythonDll(pythondll);
 				if (hPython) {
 					errors = compile_filelist(hPython, FALSE);
 					FreeLibrary(hPython);
@@ -1764,7 +1780,7 @@ InstallFilesDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 						"Compiling files to .pyo...");
 
 				SetDlgItemText(hDialog, IDC_INFO, "Loading python...");
-				hPython = LoadLibrary(pythondll);
+				hPython = LoadPythonDll(pythondll);
 				if (hPython) {
 					errors = compile_filelist(hPython, TRUE);
 					FreeLibrary(hPython);
@@ -1840,7 +1856,7 @@ FinishedDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
 			argv[0] = fname;
 
-			hPython = LoadLibrary(pythondll);
+			hPython = LoadPythonDll(pythondll);
 			if (hPython) {
 				int result;
 				result = run_installscript(hPython, fname, 2, argv);