message: makefile: fix a minor bug in Makefile
  Fix a minor in Makefile for musl static build.
diff: @@ -3,6 +3,7 @@ all: build
  TEST_WORKDIR_PREFIX ?= "/tmp"
  DOCKER ?= "true"
  +RUST_TARGET_MUSL = $(shell uname -m)-unknown-linux-musl
  RUST_TARGET ?= $(shell uname -m)-unknown-linux-musl
  CARGO ?= $(shell which cargo)
  CARGO_BUILD_GEARS = -v ~/.ssh/id_rsa:/root/.ssh/id_rsa -v ~/.cargo/git:/root/.cargo/git -v ~/.cargo/registry:/root/.cargo/registry
  @@ -56,7 +57,7 @@ endef
  ${CARGO} fmt -- --check
  .musl_target:
  - $(eval CARGO_BUILD_FLAGS += --target ${RUST_TARGET})
  + $(eval CARGO_BUILD_FLAGS += --target ${RUST_TARGET_MUSL})
  # Targets that are exposed to developers and users.
  build: .format fusedev virtiofs
  