Add cross support for arm64

Author: jfernandez

Cross.toml

@@ -1,4 +1,10 @@
 [build]
 xargo = false
 default-target = "x86_64-unknown-linux-gnu"
-pre-build = ["apt-get update && apt-get install -y zlib1g-dev libelf-dev"]
+pre-build = ["apt-get update && apt-get install -y zlib1g-dev libelf-dev"]
+
+[target.aarch64-unknown-linux-gnu]
+pre-build = [
+    "dpkg --add-architecture $CROSS_DEB_ARCH", 
+    "apt-get update && apt-get --assume-yes install zlib1g-dev:$CROSS_DEB_ARCH libelf-dev:$CROSS_DEB_ARCH"
+]

README.md

@@ -54,4 +54,5 @@ sudo ./bpftop
 ## Building from source
 
 1. Install and setup [cross](https://github.com/cross-rs/cross)
-2. Run `cross build --release`
+2. Run `cross build --release` for x86_64
+3. Run `cross build --target=aarch64-unknown-linux-gnu --release` for Arm64