Support buck2 downloads on macbooks and arm64 cpus

Makefile

@@ -29,6 +29,9 @@ ANDROID_OUT_DIR = $(OUT_DIR)/android/$(NDK_ARCH)
 ANDROID_SYSROOTS_OUT_DIR = $(OUT_DIR)/sysroots/$(NDK_ARCH)
 HOST_OUT_DIR = $(OUT_DIR)/host
 
+HOST_OS = $(shell uname -o)
+HOST_MACHINE = $(shell uname -m)
+
 export PATH:=$(abspath $(HOST_OUT_DIR)/bin):$(PATH)
 
 all:

projects/buck2/build.mk

@@ -1,17 +1,30 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 
 BUCK2_VERSION := 2023-09-01
-BUCK2_ARCHIVE := buck2.zst
-BUCK2_URL := https://github.com/facebook/buck2/releases/download/$(BUCK2_VERSION)/buck2-x86_64-unknown-linux-gnu.zst
+
+ifeq ($(HOST_OS),GNU/Linux)
+BUCK2_ARCHIVE_SUFFIX := unknown-linux-gnu
+else
+BUCK2_ARCHIVE_SUFFIX := apple-darwin
+endif
+
+ifeq ($(HOST_MACHINE),arm64)
+BUCK2_ARCHIVE_INFIX := aarch64
+else
+BUCK2_ARCHIVE_INFIX := $(HOST_MACHINE)
+endif
+
+BUCK2_ARCHIVE := buck2-$(BUCK2_ARCHIVE_INFIX)-$(BUCK2_ARCHIVE_SUFFIX).zst
+BUCK2_URL := https://github.com/facebook/buck2/releases/download/$(BUCK2_VERSION)/$(BUCK2_ARCHIVE)
 
 $(HOST_OUT_DIR)/bin/buck2: $(DOWNLOADS_DIR)/$(BUCK2_ARCHIVE) | $(HOST_OUT_DIR)
 # commands to unpack $(BUCK2_ARCHIVE) and set the executable flag
-	zstd -d $(DOWNLOADS_DIR)/$(BUCK2_ARCHIVE) -o $(HOST_OUT_DIR)/bin/buck2
-	chmod +x $(HOST_OUT_DIR)/bin/buck2
+	zstd -d $(DOWNLOADS_DIR)/$(BUCK2_ARCHIVE) -o $@
+	chmod +x $@
 
 $(DOWNLOADS_DIR)/$(BUCK2_ARCHIVE): | $(DOWNLOADS_DIR)
 # instructions to download the archive
-	wget -q -O $(DOWNLOADS_DIR)/$(BUCK2_ARCHIVE) $(BUCK2_URL)
+	wget -q -O $@ $(BUCK2_URL)
 
 # Phony target for host
 .PHONY: buck2-host