Add wrapper script around install.pl that calls buildenv.bat before doing

the install.

Dave Page

src/tools/msvc/install.bat

+@echo off
+REM $PostgreSQL: pgsql/src/tools/msvc/install.bat,v 1.1 2007/05/01 20:11:14 mha Exp $
+
+if NOT "%1"=="" GOTO RUN_INSTALL
+
+echo Invalid command line options.
+echo Usage: "install.bat <path>"
+echo.
+exit /b 1
+
+:RUN_INSTALL
+
+SETLOCAL
+if exist buildenv.bat call buildenv.bat
+
+perl install.pl "%1"
+
+exit /b %ERRORLEVEL%