Makefile: support LIBC and DESTDIR options.

Fixes:#39

Signed-off-by: Jiale Zhang <[email protected]>

Makefile

@@ -2,7 +2,6 @@ PROJDIR := $(shell readlink -f ..)
 TOP_DIR := .
 CUR_DIR := $(shell pwd)
 PREFIX := /usr/local
-BINDIR := $(PREFIX)/bin
 
 REDHATOS := $(shell cat /etc/redhat-release 2> /dev/null)
 DEBIANOS := $(shell cat /etc/debian_version 2> /dev/null)
@@ -11,19 +10,20 @@ TARGET_DIR := ./target
 BIN_NAME := attestation-agent
 
 DEBUG ?=
-MUSL ?=
+LIBC ?=
 KBC ?=
+DESTDIR ?= $(PREFIX)/bin
 
 ifdef KBC
     feature := --no-default-features --features
 endif
 
-ifdef MUSL
+ifeq ($(LIBC), musl)
     MUSL_ADD := $(shell rustup target add x86_64-unknown-linux-musl)
     ifneq ($(DEBIANOS),)
         MUSL_INSTALL := $(shell sudo apt-get install -y musl-tools) 
     endif
-    MUSL_FLAG := --target x86_64-unknown-linux-musl
+    LIBC_FLAG := --target x86_64-unknown-linux-musl
     TARGET_DIR := $(TARGET_DIR)/x86_64-unknown-linux-musl
 endif
 
@@ -45,21 +45,20 @@ ifeq ($(KBC), eaa_kbc)
 endif
 
 build:
-	$(RUST_FLAGS) cargo build $(release) $(feature) $(KBC) $(MUSL_FLAG)
+	$(RUST_FLAGS) cargo build $(release) $(feature) $(KBC) $(LIBC_FLAG)
 
 TARGET := $(TARGET_DIR)/$(BIN_NAME)
 
 install: 
-	install -D -m0755 $(TARGET) $(BINDIR)
+	install -D -m0755 $(TARGET) $(DESTDIR)
 
 uninstall:
-	rm -f $(BINDIR)/$(BIN_NAME)
+	rm -f $(DESTDIR)/$(BIN_NAME)
 
 clean:
 	cargo clean && rm -f Cargo.lock
 
 help:
-	@echo "build: make [DEBUG=1] [MUSL=1] [KBC=xxx_kbc]"
-	@echo "KBC supported:"
-	@echo "    sample_kbc"
-	@echo "    offline_fs_kbc"
+	@echo "==========================Help============================="
+	@echo "build: make [DEBUG=1] [LIBC=(musl)] [KBC=xxx_kbc]"
+	@echo "install: make install [DESTDIR=/path/to/target] [LIBC=(musl)]"

README.md

@@ -35,7 +35,7 @@ make KBC=sample_kbc
 
 To build and install with musl, just run:
 ```shell
-make MUSL=1 && make install
+make LIBC=musl && make install
 ```
 
 ### Run