chore: update README.md

fix #94

Author: qjerome

README.md

@@ -74,18 +74,20 @@ cargo xtask build --release
 
 ### Cross-compiling
 
-Let's say you want to cross-compile Kunai for aarch64 using MUSL, so that you have a single static binary at the end.
-
-1. Install the proper target using rustup `rustup install target aarch64-unknown-linux-musl`
-2. You need to install an appropriate toolchain to cross-compile to your target on your distribution. When building to a
-MUSL target, it may work using `lld` as linker and it works for `aarch64-unknown-linux-musl` target.
-3. Specify the target you want to build for in the command line and specify the linker to use.
-   ```
-   cargo xtask build --release --target aarch64-unknown-linux-musl --linker /usr/bin/lld
-   ```
-   If using `lld` does not work, you need to find the appropriate linker to use when cross-compiling to the wanted target.
-   Please dig a bit on the internet for that as I don't know them all, and it also depends on your distribution.
-4. You should find your cross-compiled binary at `./target/aarch64-unknown-linux-musl/release/kunai`
+#### aarch64
+
+1. Install the proper target using rustup `rustup install target aarch64-unknown-linux-gnu`
+2. You need to install appropriate compiler and linker to cross-compile
+```bash
+# example on ubuntu
+sudo apt install gcc-aarch64-linux-gnu
+```
+4. Cross-compile the project
+```bash
+# compile the project for with release profile
+CC=aarch64-linux-gnu-gcc  cargo xbuild --release --target aarch64-unknown-linux-gnu --linker aarch64-linux-gnu-gcc
+```
+4. You should find your cross-compiled binary at `./target/aarch64-unknown-linux-gnu/release/kunai`
 
 **NB:** specifying `--linker` option is just a shortcut for setting appropriate RUSTFLAGS env variable when building userland
 application.