Follow SCons guidance when appending defines (Arduino mbed-core)

ivankravets · ivankravets · commit 5a1e30f8875e · 2022-04-02T13:11:14.000+03:00
diff --git a/builder/frameworks/arduino/mbed-core b/builder/frameworks/arduino/mbed-core
@@ -1 +1 @@
-Subproject commit 36ee4ff8adb0d80d6ff15e03b34e7b10a147b4d0
+Subproject commit 38f9401aaf2a71225c7f62c96e7110a39ad820cf
