87d18efc7b
This also avoids an error from egrep when a header is missing. This can happen with something like WITHOUT_BLUETOOTH set when searching for $include_dir/netgraph/bluetooth/include/ng_btsocket.h. The warning was not an error (from set -e) due to being on the left side of a pipe. Now the all_headers list is only filled with existing headers. Reviewed by: ngie MFC after: 3 days Sponsored by: Dell EMC Isilon