Include configuration file to headers

Add inclusion to configration file in header files,
instead of relying on other header files to include
the configuration file. This issue resolves #1371
diff --git a/ChangeLog b/ChangeLog
index 43dfb99..167a476 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -52,6 +52,11 @@
    * Fix double initialization of ECC hardware that made some accelerators
      hang.
 
+Changes
+   * Include configuration file in all header files that use configuration,
+     instead of relying on other header files that they include.
+     Inserted as an enhancement for #1371
+
 = mbed TLS 2.14.0 branch released 2018-11-19
 
 Security