build_sdk_board: run emerge with --verbose

This provides USE flag info which can be helpful when looking at SDK logs.

BUG=chromium:1169469
TEST=CQ passes

Change-Id: I8323dc9c7e818928763666bef14995fa3ae88647
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2643860
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
diff --git a/build_sdk_board b/build_sdk_board
index 22b5158..418e8a1 100755
--- a/build_sdk_board
+++ b/build_sdk_board
@@ -140,7 +140,7 @@
 
 # Then build everything else.
 run_emerge --emptytree --with-bdeps=y \
-  --exclude "${TOOLCHAIN_PACKAGES[*]}" \
+  --exclude --verbose "${TOOLCHAIN_PACKAGES[*]}" \
   "${PACKAGES[@]}" virtual/target-sdk-nobdeps
 sudo eclean -d packages