Fix runprebuild.bat on Windows 7 systems and later

MS changed Windows 7 "reg query" command to spit out fewer lines in its preamble
Annoyingly there is no option to print raw values and not this preamble.
So now using the Windows find command.
But this has the side effect of stopping this working with Cygwin as it uses its own GNU find command.
Might fix in the future but not simple since Windows find itself is in different locations

runprebuild.bat

@@ -7,18 +7,24 @@ setlocal ENABLEEXTENSIONS
 set KEY_NAME="HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSBuild\ToolsVersions\4.0"
 set VALUE_NAME=MSBuildToolsPath
 
-FOR /F "usebackq skip=4 tokens=1-3" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_NAME% 2^>nul`) DO (
+rem We have to use find here as req query spits out 4 lines before Windows 7
+rem But 2 lines after Windows 7.  Unfortunately, this screws up cygwin
+rem as it uses its own find command.  This could be fixed but it could be
+rem complex to find the location of find on all windows systems
+FOR /F "usebackq tokens=1-3" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_NAME% 2^>nul ^| FIND "%VALUE_NAME%"`) DO (
     set ValueName=%%A
     set ValueType=%%B
     set ValueValue=%%C
 )
 
 if defined ValueName (
+    @echo Found msbuild path registry entry
     @echo Value Name = %ValueName%
     @echo Value Type = %ValueType%
     @echo Value Value = %ValueValue%
+    @echo Creating compile.bat
+    @echo %ValueValue%\msbuild opensim.sln > compile.bat
 ) else (
     @echo %KEY_NAME%\%VALUE_NAME% not found.
+    @echo Not creating compile.bat
 )
-
-@echo %ValueValue%\msbuild opensim.sln > compile.bat