Make check-names.sh find the right names in 3rdparty

Essentially adds the Everest .h and .c files to the various variables. This
should be generalized at some point, but there is no infrastructure for this
yet.
diff --git a/tests/scripts/list-identifiers.sh b/tests/scripts/list-identifiers.sh
index 4828c80..24e7404 100755
--- a/tests/scripts/list-identifiers.sh
+++ b/tests/scripts/list-identifiers.sh
@@ -35,6 +35,7 @@
     HEADERS=$( ls include/mbedtls/*_internal.h library/*.h | egrep -v 'compat-1\.3\.h|bn_mul' )
 else
     HEADERS=$( ls include/mbedtls/*.h include/psa/*.h library/*.h | egrep -v 'compat-1\.3\.h|bn_mul' )
+    HEADERS="$HEADERS 3rdparty/everest/include/everest/everest.h 3rdparty/everest/include/everest/x25519.h"
 fi
 
 rm -f identifiers