new packages: libspatialite 4.2.0, spatialite-tools, fix libfreexl pkg-config

I have managed to compile spatialite executables (spatial-extended sqlite), but some patching was done.
Could you have a look? (I'll comment the problematic places of code)
mingw32 was hardcoded in configure.ac:
```
# Checking for MinGW
AM_CONDITIONAL([MINGW], [test "$target_alias" = "mingw32"])
```
but the repacement is not a fixed string. So I have patched configure script before build.