c++11: detect and correct for boost builds with an incompatible abi

This is ugly, but temporary. boost::filesystem will likely be dropped soon
after c++11 is enabled. Otherwise, we could simply roll our own copy_file. I've
fixed this at the buildsystem level for now in order to avoid mixing in
functional changes.

Explanation:
If boost (prior to 1.57) was built without c++11, it emulated scoped enums
using c++98 constructs. Unfortunately, this implementation detail leaked into
the abi. This was fixed in 1.57.

When building against that installed version using c++11, the headers pick up
on the native c++11 scoped enum support and enable it, however it will fail to
link. This can be worked around by disabling c++11 scoped enums if linking will
fail.

Add an autoconf test to determine incompatibility. At build-time, if native
enums are being used (a c++11 build), and force-disabling them causes a
successful link, we can be sure that there's an incompatibility and enable the
work-around.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 88dc3102da..f0e1776958 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -15,6 +15,12 @@
 #include "utiltime.h"
 #include "wallet/wallet.h"
 
+#if defined(FORCE_BOOST_EMULATED_SCOPED_ENUMS)
+#define BOOST_NO_SCOPED_ENUMS
+#define BOOST_NO_CXX11_SCOPED_ENUMS
+#endif
+
+#include <boost/version.hpp>
 #include <boost/filesystem.hpp>
 #include <boost/foreach.hpp>
 #include <boost/scoped_ptr.hpp>