diff -ruN qalculate-gtk-0.9.7-orig/configure.in qalculate-gtk-0.9.7/configure.in
--- qalculate-gtk-0.9.7-orig/configure.in	2010-01-05 09:43:49.000000000 -0600
+++ qalculate-gtk-0.9.7/configure.in	2020-09-15 05:20:36.000000000 -0500
@@ -89,7 +89,7 @@
 AC_SUBST(QALCULATE_CFLAGS)
 AC_SUBST(QALCULATE_LIBS)
 
-PKG_CHECK_MODULES(CLN, [ cln >= 1.2 ],
+PKG_CHECK_MODULES(CLN, [ cln >= 9999.NOTFOUND ],
                   [have_recent_cln=yes], [have_recent_cln=no])
 AC_SUBST(CLN_CPPFLAGS)
 AC_SUBST(CLN_LIBS)
diff -ruN qalculate-gtk-0.9.7-orig/src/callbacks.cc qalculate-gtk-0.9.7/src/callbacks.cc
--- qalculate-gtk-0.9.7-orig/src/callbacks.cc	2009-12-03 16:22:49.000000000 -0600
+++ qalculate-gtk-0.9.7/src/callbacks.cc	2020-09-15 05:12:38.000000000 -0500
@@ -33,6 +33,28 @@
 #include <stack>
 #include <deque>
 
+using std::string;
+using std::vector;
+using std::list;
+using std::deque;
+using std::stack;
+// copied from libqalcualate5::includes.h
+#ifdef __GNUC__
+#   if __GNUC__ < 3
+#      include <hash_map.h>
+       namespace Sgi { using ::hash_map; }; // inherit globals
+#   else
+#      include <ext/hash_map>
+#      if __GNUC__ == 3 && __GNUC_MINOR__ == 0
+          namespace Sgi = std;               // GCC 3.0
+#      else
+          namespace Sgi = ::__gnu_cxx;       // GCC 3.1 and later
+#      endif
+#   endif
+#else      // ...  there are other compilers, right?
+    namespace Sgi = std;
+#endif
+
 extern bool do_timeout, check_expression_position;
 extern gint expression_position;
 
@@ -346,7 +368,7 @@
 			it->sort();
 		}
 	}
-	bool operator < (tree_struct &s1) const {
+	bool operator < (const tree_struct &s1) const {
 		return item < s1.item;	
 	}	
 };
diff -ruN qalculate-gtk-0.9.7-orig/src/callbacks.h qalculate-gtk-0.9.7/src/callbacks.h
--- qalculate-gtk-0.9.7-orig/src/callbacks.h	2009-12-03 16:22:49.000000000 -0600
+++ qalculate-gtk-0.9.7/src/callbacks.h	2020-09-15 05:12:01.000000000 -0500
@@ -23,6 +23,12 @@
 
 #include "main.h"
 
+using std::string;
+using std::vector;
+using std::list;
+using std::deque;
+using std::stack;
+
 struct mode_struct {
 	PrintOptions po;
 	EvaluationOptions eo;
diff -ruN qalculate-gtk-0.9.7-orig/src/interface.cc qalculate-gtk-0.9.7/src/interface.cc
--- qalculate-gtk-0.9.7-orig/src/interface.cc	2009-12-03 16:22:49.000000000 -0600
+++ qalculate-gtk-0.9.7/src/interface.cc	2020-09-15 04:07:29.000000000 -0500
@@ -31,6 +31,12 @@
 
 #include <deque>
 
+using std::string;
+using std::vector;
+using std::list;
+using std::deque;
+using std::stack;
+
 extern GladeXML *main_glade, *about_glade, *argumentrules_glade, *csvimport_glade, *csvexport_glade, *datasetedit_glade, *datasets_glade, *setbase_glade, *decimals_glade;
 extern GladeXML *functionedit_glade, *functions_glade, *matrixedit_glade, *matrix_glade, *namesedit_glade, *nbases_glade, *plot_glade, *precision_glade;
 extern GladeXML *preferences_glade, *unit_glade, *unitedit_glade, *units_glade, *unknownedit_glade, *variableedit_glade, *variables_glade;
diff -ruN qalculate-gtk-0.9.7-orig/src/main.cc qalculate-gtk-0.9.7/src/main.cc
--- qalculate-gtk-0.9.7-orig/src/main.cc	2010-01-05 09:43:49.000000000 -0600
+++ qalculate-gtk-0.9.7/src/main.cc	2020-09-15 05:07:48.000000000 -0500
@@ -27,6 +27,12 @@
 #include "callbacks.h"
 #include "main.h"
 
+using std::string;
+using std::vector;
+using std::list;
+using std::deque;
+using std::stack;
+
 MathStructure *mstruct, *matrix_mstruct, *parsed_mstruct, *parsed_tostruct;
 bool prev_result_approx;
 string *parsed_to_str;