allow a couple more environment variables to be set before running QA.

tools/auto-qa

@@ -35,13 +35,14 @@
 
 # configuration (you could tune this)
 
-EXTRA="-xfs-qa"
 BOOT="/boot"
 SOAK_PASSES="-1"
 SOAK_STRESS="10000"
 SOAK_PROC="3"
+export EXTRA=${EXTRA:=-xfs-qa}
 export MKFS_OPTIONS=${MKFS_OPTIONS:=-bsize=4096}
 export MOUNT_OPTIONS=${MOUNT_OPTIONS:=-ologbufs=2}
+export MALLOCLIB=${MALLOCLIB:=/usr/lib/libefence.a}
 
 _log()
 {
@@ -376,7 +377,6 @@ do
 		cd $WORKAREA/cmd/$pkg
 
 		# use e-fence - but this will only take effect on configure
-		export MALLOCLIB=/usr/lib/libefence.a
 		make configure 2>&1 \
 			|| _fail "	    !!! configure $pkg failed"
 		make default 2>&1 \