diff --git a/contrib/samples/stc/Makefile.in b/contrib/samples/stc/Makefile.in
index e4f7953ad2..e5c422ebe2 100644
--- a/contrib/samples/stc/Makefile.in
+++ b/contrib/samples/stc/Makefile.in
@@ -14,6 +14,7 @@ PROGRAM=stctest
 OBJECTS=$(PROGRAM).o
 
 APPEXTRALIBS=$(top_builddir)/contrib/src/stc/libstc.a
+APPEXTRADEFS=-I$(top_srcdir)/contrib/include
 
 DATAFILES=stctest.cpp
 
diff --git a/samples/stc/Makefile.in b/samples/stc/Makefile.in
index e4f7953ad2..e5c422ebe2 100644
--- a/samples/stc/Makefile.in
+++ b/samples/stc/Makefile.in
@@ -14,6 +14,7 @@ PROGRAM=stctest
 OBJECTS=$(PROGRAM).o
 
 APPEXTRALIBS=$(top_builddir)/contrib/src/stc/libstc.a
+APPEXTRADEFS=-I$(top_srcdir)/contrib/include
 
 DATAFILES=stctest.cpp