Added submodule contents into tree

externals/mbedtls/programs/util/CMakeLists.txt

@@ -0,0 +1,18 @@
+set(libs
+    ${mbedcrypto_target}
+)
+
+set(executables
+    pem2der
+    strerror
+)
+
+foreach(exe IN LISTS executables)
+    add_executable(${exe} ${exe}.c $<TARGET_OBJECTS:mbedtls_test>)
+    target_link_libraries(${exe} ${libs} ${CMAKE_THREAD_LIBS_INIT})
+    target_include_directories(${exe} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../../tests/include)
+endforeach()
+
+install(TARGETS ${executables}
+        DESTINATION "bin"
+        PERMISSIONS OWNER_READ OWNER_WRITE OWNER_EXECUTE GROUP_READ GROUP_EXECUTE WORLD_READ WORLD_EXECUTE)