patch 8.1.0403: header file missing from distribution

Problem:    Header file missing from distribution.
Solution:   Add src/protodef.h.
diff --git a/Filelist b/Filelist
index 59415d3..5fe085e 100644
--- a/Filelist
+++ b/Filelist
@@ -141,6 +141,7 @@
 		src/testdir/if_ver*.vim \
 		src/testdir/color_ramp.vim \
 		src/proto.h \
+		src/protodef.h \
 		src/proto/arabic.pro \
 		src/proto/beval.pro \
 		src/proto/blowfish.pro \
diff --git a/src/version.c b/src/version.c
index a8be96c..30b79de 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    403,
+/**/
     402,
 /**/
     401,