minor: restore limited build on 32-bit Windows

acmorrow · acmorrow · commit a51cd76af03a · 2015-05-12T12:30:32.000-04:00
diff --git a/.mci.yml b/.mci.yml
@@ -575,6 +575,7 @@ buildvariants:
     <<: *parallel_compile_flags_proc
     <<: *mongo_url_windows32
     <<: *with_msvc2010_32bit
+    compile_target: driver build-unit
   run_on:
   - windows-64-compile
   tasks:
