clang: error: cannot user typeid with -fno-rtti in node/RingBuffer.hpp

[dch]

Describe the bug

Build fails with default options on FreeBSD 12.0-RC2 with current clang (v6).

node/RingBuffer.hpp:333:8: error: cannot use typeid with -fno-rtti
                        if (typeid(T) == typeid(int)) {
                            ^
node/RingBuffer.hpp:333:21: error: cannot use typeid with -fno-rtti
                        if (typeid(T) == typeid(int)) {

To Reproduce

$ gsh
commit 9d2bc9bf4e2c0be7f763297c5509e995703747d0 (HEAD -> dev, upstream/dev)
Merge: 5da7d6d1 52c4385c
Author: Adam Ierymenko <adam.ierymenko@gmail.com>
Date:   Wed Nov 28 08:44:45 2018 -0800

    Merge branch 'master' into dev

dch@wintermute /r/zt> uname -a
FreeBSD wintermute.skunkwerks.at 12.0-PRERELEASE FreeBSD 12.0-PRERELEASE r340921+548174329ec8(stable/12) GENERIC  amd64

dch@wintermute /r/zt> clang -v
FreeBSD clang version 6.0.1 (tags/RELEASE_601/final 335540) (based on LLVM 6.0.1)
Target: x86_64-unknown-freebsd12.0
Thread model: posix
InstalledDir: /usr/bin

dch@wintermute /r/zt> gmake
clang++ -O3 -fstack-protector -Wall -fPIE -fvisibility=hidden -fstack-protector -pthread  -DNDEBUG  -DZT_USE_X64_ASM_SALSA2012 -DZT_BUILD_PLATFORM=7 -DZT_BUILD_ARCHITECTURE=2 -DZT_SOFTWARE_UPDATE_DEFAULT="\"disable\"" -fno-rtti -std=c++11    -c -o node/C25519.o node/C25519.cpp
clang++ -O3 -fstack-protector -Wall -fPIE -fvisibility=hidden -fstack-protector -pthread  -DNDEBUG  -DZT_USE_X64_ASM_SALSA2012 -DZT_BUILD_PLATFORM=7 -DZT_BUILD_ARCHITECTURE=2 -DZT_SOFTWARE_UPDATE_DEFAULT="\"disable\"" -fno-rtti -std=c++11    -c -o node/Capability.o node/Capability.cpp
In file included from node/Capability.cpp:30:
In file included from node/Topology.hpp:43:
In file included from node/Peer.hpp:36:
In file included from node/Node.hpp:46:
In file included from node/Path.hpp:42:
node/RingBuffer.hpp:333:8: error: cannot use typeid with -fno-rtti
                        if (typeid(T) == typeid(int)) {
                            ^
node/RingBuffer.hpp:333:21: error: cannot use typeid with -fno-rtti
                        if (typeid(T) == typeid(int)) {
                                         ^
2 errors generated.
gmake: *** [<builtin>: node/Capability.o] Error 1

Expected behavior

Build compiles OOTB

Screenshots

Desktop (please complete the following information):

• OS: FreeBSD 12.0-RC2 (almost the real thing now!)
• ZeroTier Version: dev branch 9d2bc9b
• Hardware: Intel Xeon v2667v4 😁

[Crest]

This is caused by invoking the compiler with -fno-rtti in make-bsd.mk. Removing it from CXXFLAGS+= allows the default gmake targets to build.