Merge pull request #2 from VCVRack/docker-build-fixes

Docker build fixes

Dockerfile

@@ -30,4 +30,7 @@ RUN make toolchain-mac
 RUN make toolchain-win
 RUN make toolchain-lin
 
+# Install Rack SDK
+RUN make rack-sdk
+
 RUN rm MacOSX10.13.sdk.tar.*

Makefile

@@ -186,7 +186,7 @@ docker-build:
 
 DOCKER_RUN := docker run --rm --interactive --tty \
 	--volume=$(PLUGIN_DIR):/home/build/plugin-src \
-	--volume=$(PWD)/$(PLUGIN_BUILD_DIR):/home/build/$(PLUGIN_BUILD_DIR) \
+	--volume=$(PWD)/$(PLUGIN_BUILD_DIR):/home/build/rack-plugin-toolchain/$(PLUGIN_BUILD_DIR) \
 	--env PLUGIN_DIR=/home/build/plugin-src \
 	rack-plugin-toolchain:1 \
 	/bin/bash