diff --git a/flang/runtime/CMakeLists.txt b/flang/runtime/CMakeLists.txt
--- a/flang/runtime/CMakeLists.txt
+++ b/flang/runtime/CMakeLists.txt
@@ -25,6 +25,10 @@
 endif()
 
 configure_file(config.h.cmake config.h)
+# include_directories is used here instead of target_include_directories
+# because add_flang_library creates multiple objects (STATIC/SHARED, OBJECT)
+# with different names
+include_directories(AFTER ${CMAKE_CURRENT_BINARY_DIR})
 
 add_flang_library(FortranRuntime
   ISO_Fortran_binding.cpp