plugins/Makefile has target/${RUST_PROFILE}/cln-grpc depend on the
generated files via $(MSGGEN_GENALL), but cln-rpc/Makefile adds to
that variable, so needs to be included first.
Here's an example build error:
```
Combining schemas from /home/rusty/lightning-ltest/doc/schemas into /home/rusty/lightning-ltest/contrib/msggen/msggen/schema.json
Created /home/rusty/lightning-ltest/contrib/msggen/msggen/schema.json from 2 files
error: failed to run custom build command for `cln-grpc v0.3.0 (/home/rusty/lightning-ltest/cln-grpc)`
Caused by:
process didn't exit successfully: `/home/rusty/lightning-ltest/target/debug/build/cln-grpc-95489e3ba33c0ab3/build-script-build` (exit status: 101)
--- stdout
cargo:rerun-if-changed=proto/node.proto
cargo:rerun-if-changed=proto
--- stderr
thread 'main' panicked at cln-grpc/build.rs:7:10:
called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: "protoc failed: node.proto:134:52: \"AskreneageResponse\" is not defined.\nnode.proto:135:23: \"GetroutesRequest\" is not defined.\nnode.proto:135:50: \"GetroutesResponse\" is not defined.\nnode.proto:136:32: \"AskrenedisablenodeRequest\" is not defined.\nnode.proto:136:68: \"AskrenedisablenodeResponse\" is not defined.\nnode.proto:137:34: \"AskreneinformchannelRequest\" is not defined.\nnode.proto:137:72: \"AskreneinformchannelResponse\" is not defined.\nnode.proto:138:34: \"AskrenecreatechannelRequest\" is not defined.\nnode.proto:138:72: \"AskrenecreatechannelResponse\" is not defined.\nnode.proto:139:34: \"AskreneupdatechannelRequest\" is not defined.\nnode.proto:139:72: \"AskreneupdatechannelResponse\" is not defined.\nnode.proto:140:32: \"AskrenebiaschannelRequest\" is not defined.\nnode.proto:140:68: \"AskrenebiaschannelResponse\" is not defined.\nnode.proto:141:37: \"AskrenelistreservationsRequest\" is not defined.\nnode.proto:141:78: \"AskrenelistreservationsResponse\" is not defined.\nnode.proto:142:32: \"InjectpaymentonionRequest\" is not defined.\nnode.proto:142:68: \"InjectpaymentonionResponse\" is not defined.\nnode.proto:143:18: \"XpayRequest\" is not defined.\nnode.proto:143:40: \"XpayResponse\" is not defined.\nnode.proto:145:33: \"StreamBlockAddedRequest\" is not defined.\nnode.proto:145:74: \"BlockAddedNotification\" is not defined.\nnode.proto:146:40: \"StreamChannelOpenFailedRequest\" is not defined.\nnode.proto:146:88: \"ChannelOpenFailedNotification\" is not defined.\nnode.proto:147:36: \"StreamChannelOpenedRequest\" is not defined.\nnode.proto:147:80: \"ChannelOpenedNotification\" is not defined.\nnode.proto:148:30: \"StreamConnectRequest\" is not defined.\nnode.proto:148:68: \"PeerConnectNotification\" is not defined.\nnode.proto:149:32: \"StreamCustomMsgRequest\" is not defined.\nnode.proto:149:72: \"CustomMsgNotification\" is not defined.\n" }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
make: *** [plugins/Makefile:305: target/debug/cln-grpc] Error 101
make: *** Waiting for unfinished jobs....
```
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Plugin Directory
Any file in this directory which is executable and whose name only consists of alphanumeric characters, space, '.', '-' or '_' will be automatically loaded when lightningd starts (unless suppressed with commandline options).