The default C++ compiler that comes with OpenBSD 5.7 is g++ 4.2. This version is old (from 2007), and is not able to compile the current version of Bitcoin Core. It is possible to patch it up to compile, but with the planned transition to C++11 this is a losing battle. So here we will be installing a newer compiler.
GCC
-------
You can install a newer version of gcc with:
```bash
pkg_add g++ # (select newest 4.x version, e.g. 4.9.2)
```
This compiler will not overwrite the system compiler, it will be installed as `egcc` and `eg++` in `/usr/local/bin`.
### Building boost
Do not use `pkg_add boost`! The boost version installed thus is compiled using the `g++` compiler not `eg++`, which will result in a conflict between `/usr/local/lib/libestdc++.so.XX.0` and `/usr/lib/libstdc++.so.XX.0`, resulting in a test crash:
test_bitcoin:/usr/lib/libstdc++.so.57.0: /usr/local/lib/libestdc++.so.17.0 : WARNING: symbol(_ZN11__gnu_debug17_S_debug_me ssagesE) size mismatch, relink your program
...
Segmentation fault (core dumped)
This makes it necessary to build boost, or at least the parts used by Bitcoin Core, manually:
```
# Pick some path to install boost to, here we create a directory within the bitcoin directory
BITCOIN_ROOT=$(pwd)
BOOST_PREFIX="${BITCOIN_ROOT}/boost"
mkdir -p $BOOST_PREFIX
# Fetch the source and verify that it is not tampered with
# Also here: https://gist.githubusercontent.com/laanwj/bf359281dc319b8ff2e1/raw/92250de8404b97bb99d72ab898f4a8cb35ae1ea3/patch-boost_test_impl_execution_monitor_ipp.patch
However, this does not appear to work. Compilation succeeds, but link fails
with many 'local symbol discarded' errors:
local symbol 150: discarded in section `.text._ZN10tinyformat6detail14FormatIterator6finishEv' from libbitcoin_util.a(libbitcoin_util_a-random.o)
local symbol 151: discarded in section `.text._ZN10tinyformat6detail14FormatIterator21streamStateFromFormatERSoRjPKcii' from libbitcoin_util.a(libbitcoin_util_a-random.o)
local symbol 152: discarded in section `.text._ZN10tinyformat6detail12convertToIntIA13_cLb0EE6invokeERA13_Kc' from libbitcoin_util.a(libbitcoin_util_a-random.o)
According to similar reported errors this is a binutils (ld) issue in 2.15, the