Description

I'm not satisfied with the LLVM integration / compatibility in RIOT.
In order to assess the current state of it, I tried compiling the examples using LLVM.
14 out of 59 examples do not build using LLVM.
Is this correct / expected or am I using it wrong? 🤓

Steps to reproduce the issue

A script similar to this one was used to produce the results:

#!/bin/bash
cd riot/examples/;
for i in *;
do
        cd $i;
        if TOOLCHAIN=llvm make -j10 &> /dev/null; then
                echo $i ✅
        else
                echo $i ❌
        fi
        cd ..;
done

Expected results

All examples build fine using LLVM.

Actual results

If an example builds fine it is marked with ✅
Some examples fail to build using LLVM. Those are marked with ❌.
The examples that fail with non LLVM related issues are marked with brackets.

arduino_hello-world ❌
asymcute_mqttsn ✅
benchmark_udp ✅
bindist ✅
blinky ✅
[ccn-lite-relay ❌ cmake]
cord_ep ✅
cord_epsim ✅
cord_lc ✅
default ✅
dtls-echo ✅
dtls-sock ✅
dtls-wolfssl ✅
emcute_mqttsn ✅
filesystem ❌
gcoap ✅
gcoap_block_server ✅
gcoap_dtls ✅
gcoap_fileserver ❌
gnrc_border_router ✅
gnrc_lorawan ❌
gnrc_minimal ✅
gnrc_networking ❌
gnrc_networking_mac ❌
gnrc_networking_subnets ❌
hello-world ✅
ipc_pingpong ✅
[javascript ❌ cmake]
lorawan ❌
lua_REPL ❌
lua_basic ❌
[micropython ❌ llvm blacklisted]
nanocoap_server ✅
ndn-ping ✅
nimble_gatt ❌
nimble_heart_rate_sensor ❌
nimble_scanner ✅
[openthread ❌ llvm blacklisted]
paho-mqtt ✅
posix_select ✅
posix_sockets ✅
[riot_and_cpp ❌ c++]
[rust-gcoap ❌ no rustup]
[rust-hello-world ❌ no rustup]
saul ✅
senml_saul ✅
skald_eddystone ✅
skald_ibeacon ✅
sniffer ✅
spectrum-scanner ✅
suit_update ❌
telnet_server ✅
thread_duel ✅
timer_periodic_wakeup ✅
twr_aloha ❌
usbus_minimal ✅
wakaama ❌
[wasm ❌ cmake]