Let tests/sscpp706 find its data in VPATH builds as well

tests/Makefile.am

@@ -12,6 +12,7 @@ AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/src
 LDADD = ../src/liblog4shib.la
 AM_DEFAULT_SOURCE_EXT = .cpp
 
+sscpp706_CPPFLAGS = $(AM_CPPFLAGS) -DDATADIR=\"$(srcdir)\"
 
 testbench_SOURCES = Clock.cpp Clock.hh testbench.cpp 
 

tests/sscpp706.cpp

@@ -5,7 +5,7 @@
 
 int main(int argc, char* argv[])
 {
-    std::string initFileName = argc > 1 ? argv[1] : "sscpp706.txt";
+    std::string initFileName = argc > 1 ? argv[1] : DATADIR "/sscpp706.txt";
     try {
         log4shib::PropertyConfigurator::configure(initFileName);
         log4shib::Category& root = log4shib::Category::getRoot();