In compiling Inkscape for Windows vista Home SP2, in response to the 'btool' command, I received  this error message: 

make error line 0 ： cannot open the file 'C:\devlibs\lib\pkgconfig\gtkmm-2.4.pc'

Adding the DEVLIBS_PATH fixed this problem, ran btool again, but received similar message for mingw, adding the MINGW_PATH environment variable fixed this problem as well.

How to:
In Control Panel/System/Advanced System Settings/Advanced Tab/Environment Variables:
1. click New, type DEVLIBS_PATH in Variable Name, C:\<path>\devlibs in Variable Value, click OK ...(individual paths may vary)
2. click New, type MINGW_PATH in Variable Name, C:\mingw32 in Variable Value, click OK 

3. click OK, close control panel, etc.
4. run btool again
5. play skyrim while it grinds

- susan