Merge #15308: build: Restore compatibility with older boost

119d360aab travis: Document whether functional tests are run in the job name (Ben Woosley)
64f28545e3 Revert "travis: Compile trusty with depends for now" (Ben Woosley)
267eac00f9 Prefer boost::optional#get_value_or over #value_or (Ben Woosley)
1971f5ba04 Piecewise construct to avoid invalid construction (Ben Woosley)

Pull request description:

  In light of #14979, I realized that only qt 5.5+ was being tested under CI, while compatibility lists 5.2+.

  In #15276, Marco added Trusty to CI, building with depends. This changes that build to system libraries, in order to ensure ongoing compatibility with our claimed minimum required versions.

  Fixes #14983, previously open as #14998

Tree-SHA512: 6cff5e28c756ecb8bf797c8f6eb77c1944ba61a8dd6d7d4984e63eef384f6429dc79c505da3241c05b9c4db31c72b2a9846c7365aba9280f2e0620e5f3998d07

1 files changed, 5 insertions, 1 deletions

diff --git a/src/validationinterface.cpp b/src/validationinterface.cpp
index 533d41288..2e13bef19 100644
--- a/src/validationinterface.cpp
+++ b/src/validationinterface.cpp
@@ -14,6 +14,7 @@
 #include <list>
 #include <atomic>
 #include <future>
+#include <utility>
 
 #include <boost/signals2/signal.hpp>
 
@@ -77,7 +78,10 @@ size_t CMainSignals::CallbacksPending() {
 }
 
 void CMainSignals::RegisterWithMempoolSignals(CTxMemPool& pool) {
-    g_connNotifyEntryRemoved.emplace(&pool, pool.NotifyEntryRemoved.connect(std::bind(&CMainSignals::MempoolEntryRemoved, this, std::placeholders::_1, std::placeholders::_2)));
+    g_connNotifyEntryRemoved.emplace(std::piecewise_construct,
+        std::forward_as_tuple(&pool),
+        std::forward_as_tuple(pool.NotifyEntryRemoved.connect(std::bind(&CMainSignals::MempoolEntryRemoved, this, std::placeholders::_1, std::placeholders::_2)))
+    );
 }
 
 void CMainSignals::UnregisterWithMempoolSignals(CTxMemPool& pool) {