Since I have been wasting some hours on this and could not find hints on the web about it easily:
When you need to install STLport for Pocket PCs with Microsofts embedded Visual C++ (bingo!) and it the compiler complains about missing windefs.h or similar during installation/compilation chech the environment variables. There already is a nice description of how to do it but it forgets one thing: The program "C:\Program Files\Microsoft eMbedded C++ 4.0\EVC\wce420\bin\WCEARMV4.BAT" does not produce the right environment if you have installed the Windows CE Tools in a nonstandard directory. You will need to adjust %INCLUDE% to match your paths.
Next Problem will be the coredll.lib library which most likely is also missing from your path. You will need to adjust <em>%LIB%</em>. Also to avoid this error
_STLP_DEBUG mode is not supported in evc3 and evc4 on the ARM platform!
you need to
nmake /fevc.mak clean install-release-shared install-release-static
So on my system both look like this:
D:\STLport-5.1.4\STLport-5.1.4\build\lib>echo %include% D:\Programme\Windows CE Tools\wce420\POCKET PC 2003\Include\Armv4;D:\Programme\Windows CE Tools\wce420\POCKET PC 2003\Mfc\Include;D:\Programme\Windows CE Tools\wce420\POCKET PC 2003\Atl\Include D:\STLport-5.1.4\STLport-5.1.4\build\lib>echo %lib% D:\Programme\Windows CE Tools\wce420\POCKET PC 2003\Lib\Armv4;D:\Programme\Windows CE Tools\wce420\POCKET PC 2003\Mfc\Lib;D:\Programme\Windows CE Tools\wce420\POCKET PC 2003\Atl\Lib
YMMV.