Makefile cleanup, default to binary prefix

mk/config.mk

@@ -1,34 +1,48 @@
 # Configuration
+## Architecture to build Redox for (aarch64 or x86_64)
 ARCH?=x86_64
+## Flags to pass to the installer (empty to download binary packages)
 INSTALLER_FLAGS?=--cookbook=cookbook
-PREFIX_BINARY?=0
+## Enabled to use binary prefix (much faster)
+PREFIX_BINARY?=1
+## Enabled to build custom rustc
 PREFIX_RUSTC?=0
-# Filesystem Size in MB
+## Filesystem size in MB (256 is the default)
 FILESYSTEM_SIZE?=256
 
 # Per host variables
 UNAME := $(shell uname)
 ifeq ($(UNAME),Darwin)
-	ECHO=/bin/echo
 	FUMOUNT=sudo umount
 	export NPROC=sysctl -n hw.ncpu
+	PREFIX_BINARY=0
 	VB_AUDIO=coreaudio
-	VBM="/Applications/VirtualBox.app/Contents/MacOS/VBoxManage"
+	VBM=/Applications/VirtualBox.app/Contents/MacOS/VBoxManage
 else
-	ECHO=echo
 	FUMOUNT=fusermount -u
 	export NPROC=nproc
-	VB_AUDIO="pulse"
+	VB_AUDIO=pulse
 	VBM=VBoxManage
 endif
 
 # Automatic variables
-ROOT=$(PWD)
+ROOT=$(CURDIR)
 export RUST_TARGET_PATH=$(ROOT)/kernel/targets
 export XARGO_HOME=$(ROOT)/build/xargo
 export XARGO_RUST_SRC=$(ROOT)/rust/src
 
-# Cross compiler variables
+## Kernel variables
+KTARGET=$(ARCH)-unknown-none
+KBUILD=build/kernel
+
+## Userspace variables
+export TARGET=$(ARCH)-unknown-redox
+BUILD=build/userspace
+
+## Bootloader variables
+EFI_TARGET=$(ARCH)-efi-pe
+
+## Cross compiler variables
 AR=$(TARGET)-gcc-ar
 AS=$(TARGET)-as
 CC=$(TARGET)-gcc
@@ -41,18 +55,7 @@ RANLIB=$(TARGET)-gcc-ranlib
 READELF=$(TARGET)-readelf
 STRIP=$(TARGET)-strip
 
-# Rust cross compile variables
+## Rust cross compile variables
 export AR_$(subst -,_,$(TARGET))=$(TARGET)-ar
 export CC_$(subst -,_,$(TARGET))=$(TARGET)-gcc
 export CXX_$(subst -,_,$(TARGET))=$(TARGET)-g++
-
-# Bootloader variables
-EFI_TARGET=$(ARCH)-efi-pe
-
-# Kernel variables
-KTARGET=$(ARCH)-unknown-none
-KBUILD=build/kernel
-
-# Userspace variables
-export TARGET=$(ARCH)-unknown-redox
-BUILD=build/userspace