Adds a dev target to Makefile and ports over build script (#75)

* Initial work on dev builds

* Fix build script

scripts/protoc_gen_plugin.bash

@@ -0,0 +1,89 @@
+#!/usr/bin/env bash
+
+# Copied with minor changes from Makego at https://github.com/bufbuild/makego/blob/master/make/go/scripts/protoc_gen_plugin.bash
+
+set -eo pipefail
+
+fail() {
+  echo "$@" >&2
+  exit 1
+}
+
+usage() {
+  echo "usage: ${0} \
+    --proto_path=path/to/one \
+    --proto_path=path/to/two \
+    --proto_include_path=path/to/one \
+    --proto_include_path=path/to/two \
+    --plugin_name=go \
+    --plugin_out=gen/proto/go \
+    --plugin_opt=plugins=grpc"
+}
+
+check_flag_value_set() {
+  if [ -z "${1}" ]; then
+    usage
+    exit 1
+  fi
+}
+
+PROTO_PATHS=()
+PROTO_INCLUDE_PATHS=()
+PLUGIN_NAME=
+PLUGIN_OUT=
+PLUGIN_OPT=
+while test $# -gt 0; do
+  case "${1}" in
+    -h|--help)
+      usage
+      exit 0
+      ;;
+    --proto_path*)
+      PROTO_PATHS+=("$(echo ${1} | sed -e 's/^[^=]*=//g')")
+      shift
+      ;;
+    --proto_include_path*)
+      PROTO_INCLUDE_PATHS+=("$(echo ${1} | sed -e 's/^[^=]*=//g')")
+      shift
+      ;;
+    --plugin_name*)
+      PLUGIN_NAME="$(echo ${1} | sed -e 's/^[^=]*=//g')"
+      shift
+      ;;
+    --plugin_out*)
+      PLUGIN_OUT="$(echo ${1} | sed -e 's/^[^=]*=//g')"
+      shift
+      ;;
+    --plugin_opt*)
+      PLUGIN_OPT="$(echo ${1} | sed -e 's/^[^=]*=//g')"
+      shift
+      ;;
+    *)
+      usage
+      exit 1
+      ;;
+  esac
+done
+
+check_flag_value_set "${PROTO_PATHS[@]}"
+check_flag_value_set "${PLUGIN_NAME}"
+check_flag_value_set "${PLUGIN_OUT}"
+
+PROTOC_FLAGS=()
+for proto_path in "${PROTO_PATHS[@]}"; do
+  PROTOC_FLAGS+=("--proto_path=${proto_path}")
+done
+for proto_path in "${PROTO_INCLUDE_PATHS[@]}"; do
+  PROTOC_FLAGS+=("--proto_path=${proto_path}")
+done
+PROTOC_FLAGS+=("--${PLUGIN_NAME}_out=${PLUGIN_OUT}")
+if [ -n "${PLUGIN_OPT}" ]; then
+  PROTOC_FLAGS+=("--${PLUGIN_NAME}_opt=${PLUGIN_OPT}")
+fi
+
+for proto_path in "${PROTO_PATHS[@]}"; do
+  for dir in $(find "${proto_path}" -name '*.proto' -print0 | xargs -0 -n1 dirname | sort | uniq); do
+    echo protoc "${PROTOC_FLAGS[@]}" $(find "${dir}" -name '*.proto')
+    protoc "${PROTOC_FLAGS[@]}" $(find "${dir}" -name '*.proto')
+  done
+done