Building current HEAD (5468b69) with:

/usr/local/lib/qt5/bin/qmake \
        QMAKE_CXXFLAGS="-g -ggdb3 -I/usr/local/include" \
        QMAKE_LIBS="-lcxxrt -L/usr/local/lib" \
        -r
make debug

tinky:~/w/qcad/qcad$ ../qcad.sh
Launching QCAD debug
QCAD version  3.15.5.7
RPluginLoader.cpp:67, static QStringList RPluginLoader::getPluginFiles():
11:25:06: Debug:    Ignoring release plugin built in debug mode:  "libqcadexample.so"
RPluginLoader.cpp:67, static QStringList RPluginLoader::getPluginFiles():
11:25:06: Debug:    Ignoring release plugin built in debug mode:  "libtransactionlistener.so"
RDxfPlugin.cpp:9, virtual bool RDxfPlugin::init():
11:25:06: Debug:    RDxfPlugin::init
RDebug.cpp:81, static int RDebug::stopTimer(int, const QString &, int):
11:25:15: Debug:    TIMER:  1038000000 ns ( 1038 ms )  -  "loading add-ons"
RDebug.cpp:81, static int RDebug::stopTimer(int, const QString &, int):
11:25:19: Debug:    TIMER:  18446744073365584320 ns ( 18446744073365 ms )  -  "initializing add-ons"
RScriptHandlerEcma.cpp:1468, static QScriptValue RScriptHandlerEcma::ecmaMessageHandler(QScriptContext *, QScriptEngine *, RS::MessageType):

For whatever reason, libqcadexample.so and libtransactionlistener.so don't get named _debug.so (which seems to be the cause for the message), while libqcaddxf_debug.so seems to be OK.

The following diff sorts this out, with no apparent ill effect:

diff --git a/support/examples/exampleplugin/exampleplugin.pro b/support/examples/exampleplugin/exampleplugin.pro
index 0c58c56..d72a866 100644
--- a/support/examples/exampleplugin/exampleplugin.pro
+++ b/support/examples/exampleplugin/exampleplugin.pro
@@ -1,7 +1,8 @@
-include(../../../shared.pri)
 CONFIG      += plugin
 TARGET      = $${RLIBNAME}example
 
+include(../../../shared.pri)
+
 TEMPLATE    = lib
 HEADERS     = RExamplePlugin.h
 SOURCES     = RExamplePlugin.cpp
diff --git a/support/examples/transactionlistener/transactionlistener.pro b/support/examples/transactionlistener/transactionlistener.pro
index ed6c84d..7ee9bef 100644
--- a/support/examples/transactionlistener/transactionlistener.pro
+++ b/support/examples/transactionlistener/transactionlistener.pro
@@ -1,7 +1,8 @@
-include(../../../shared.pri)
 CONFIG      += plugin
 TARGET      = transactionlistener
 
+include(../../../shared.pri)
+
 TEMPLATE    = lib
 HEADERS     = TransactionListenerPlugin.h
 SOURCES     = TransactionListenerPlugin.cpp