F15: gcc-4.6.0 producing 0-length objects!?

[Neal Becker]

Trying to build boost-1.46.1:
 
  "g++"  -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -fPIC  -
DBOOST_ALL_NO_LIB=1 -DBOOST_SIGNALS_DYN_LINK=1 -DBOOST_SIGNALS_NO_LIB=1 -DNDEBUG  
-I"." -c -o "bin.v2/libs/signals/build/gcc-4.6.0/release/trackable.o" 
"libs/signals/src/trackable.cpp"

[nbecker at nbecker1 boost_1_46_1.hg]$ ls -l 
bin.v2/libs/signals/build/gcc-4.6.0/release/trackable.o 

-rw-rw-r--. 1 nbecker nbecker 0 May 13 19:37 
bin.v2/libs/signals/build/gcc-4.6.0/release/trackable.o

What could possibly cause this (100% repeatable)?