- for the native target gcc, drop --enable-optspace in favour of using the...

- for the native target gcc, drop --enable-optspace in favour of using the configured flags (that default to -Os anyway).
  Saves about 20% size without additional configure args:
   text    data     bss     dec     hex filename
4685000   17280  566360 5268640  5064a0 optspace/i586-linux-uclibc/4.2.0/cc1
3630655   15184  562172 4208011  40358b usrflags/i586-linux-uclibc/4.2.0/cc1
4853646   23532  568528 5445706  53184a optspace/i586-linux-uclibc/4.2.0/f951
3772121   21292  564148 4357561  427db9 usrflags/i586-linux-uclibc/4.2.0/f951