diff --git a/src/roofitcore/CMakeLists.txt b/src/roofitcore/CMakeLists.txt
index 3de3138..095a17a 100644
--- a/src/roofitcore/CMakeLists.txt
+++ b/src/roofitcore/CMakeLists.txt
@@ -468,6 +468,7 @@ target_link_libraries(RooFitCore PUBLIC
     MathCore
     Foam
     Smatrix
+    TestSupport
     ${EXTRA_DEPENDENCIES}
 )
 
diff --git a/src/roofitcore/inc/RooFit/Config.h b/src/roofitcore/inc/RooFit/Config.h
index bec2c9d..d6e9d4d 100644
--- a/src/roofitcore/inc/RooFit/Config.h
+++ b/src/roofitcore/inc/RooFit/Config.h
@@ -17,6 +17,8 @@
 // memory safe.
 // #define ROOFIT_MEMORY_SAFE_INTERFACES
 
+#include <ROOT/RConfig.hxx>
+
 #include <memory>
 
 namespace RooFit {
@@ -59,8 +61,10 @@ OwningPtr<T> makeOwningPtr(std::unique_ptr<U> &&ptr)
 
 } // namespace RooFit
 
-#ifndef R__DEPRECATED
-# define R__DEPRECATED(X, Y, Z)
+// Define required deprecation macros if the ROOT version that we build RooFit
+// against doesn't have it.
+#ifndef _R__DEPRECATED_636
+# define _R__DEPRECATED_636(REASON) _R__DEPRECATED_LATER(REASON)
 #endif
 
 #endif
diff --git a/src/testsupport/CMakeLists.txt b/src/testsupport/CMakeLists.txt
index d3c58e2..621c82d 100644
--- a/src/testsupport/CMakeLists.txt
+++ b/src/testsupport/CMakeLists.txt
@@ -7,11 +7,8 @@
 set(libname TestSupport)
 set(header_dir ROOT/)
 
-add_library(${libname} OBJECT src/TestSupport.cxx)
-target_include_directories(${libname} PUBLIC
-  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/inc/>
-  $<INSTALL_INTERFACE:./>
-  )
+add_library(${libname} SHARED src/TestSupport.cxx)
+target_include_directories(${libname} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/inc)
 target_link_libraries(${libname} PUBLIC Core gtest)
 
 # Installation of header and library: