Replace config.toml with ENV vars [skip ci]

Author: Claudio Raimondi

Dockerfile

@@ -141,12 +141,10 @@ ARG TARGET=${target_arch_rust}
 ARG PKG_CONFIG_PATH=/usr/lib/${target_arch}/pkgconfig
 ARG COPTFLAGS="-O2 ${COPTFLAGS}"
 
-#TODO: find a way to set these in ENV isntead of writing into config.toml
-RUN mkdir -p .cargo && tee .cargo/config.toml <<EOF
-[target.${target_arch_rust}]
-linker = "${target_arch}-gcc"
-rustflags = ["-C", "target-cpu=generic"]
-EOF
+ARG CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=${CC}
+ARG CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER=${CC}
+ARG CARGO_TARGET_ARMV7_UNKNOWN_LINUX_GNUEABIHF_LINKER=${CC}
+ARG RUSTFLAGS="-C target-cpu=generic"
 
 WORKDIR /opt