I suggest to accept also the option -d which is then passed to emerge.

When crossdev fails it is often necessary to call emerge with the -d 
option, in order to find the cause of the failure.

--- crossdev	2005-09-14 00:17:10.000000000 +0200
+++ crossdev_0.9.9_debug_kob	2005-10-07 17:49:55.000000000 +0200
@@ -31,7 +31,7 @@
     ${GOOD}--k, --kernel${NORMAL} ver     Specify version of kernel headers to use
     ${GOOD}--l, --libc${NORMAL} ver       Specify version of libc to use
     ${GOOD}-C, --clean${NORMAL} target    Uninstall specified target
-    ${GOOD}-b, -p, -v${NORMAL}            Options to pass to emerge (see emerge(1))
+    ${GOOD}-b, -d, -p, -v${NORMAL}            Options to pass to emerge (see emerge(1))
 Basic Targets:
     ${GOOD}-s0, --stage0${NORMAL}         Build just binutils
     ${GOOD}-s1, --stage1${NORMAL}         Also build a C compiler (no libc/C++)
@@ -267,7 +267,7 @@
 	--ex-only)      EX_FAST="yes";;
 	--ex-gcc)       EX_GCC="yes";;
 	--ex-gdb)       EX_GDB="yes";;
-	-b|-p|-v)       UOPTS="${UOPTS} $1";;
+	-b|-p|-v|-d)    UOPTS="${UOPTS} $1";;
 	-pv|-vp)        UOPTS="${UOPTS} -p -v";;
 	-h|--help)      usage;;
 	-*)             eerror "UNKNOWN OPTION: '$1'" ; usage 1;;