icu: fix build with gcc >= 4.4 / JLEVEL > 1

Fix two issues with the icu build:
- icu source contains an #elif without any arguments, which g++ >= 4.4
  flags as an error. This is both an issue for target and host build,
  so restructure the .mk so any *both*patch is applied to both builds
  (the other patches would cause trouble with host builds)
- icu build system isn't parallel make safe, use MAKE1

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>