patch 8.1.2077: the ops.c file is too big

Problem:    The ops.c file is too big.
Solution:   Move code for dealing with registers to a new file. (Yegappan
            Lakshmanan, closes #4982)
diff --git a/Filelist b/Filelist
index 7c5a4f0..ff9d439 100644
--- a/Filelist
+++ b/Filelist
@@ -100,6 +100,7 @@
 		src/regexp_bt.c \
 		src/regexp_nfa.c \
 		src/regexp.h \
+		src/register.c \
 		src/scriptfile.c \
 		src/screen.c \
 		src/search.c \
@@ -244,6 +245,7 @@
 		src/proto/profiler.pro \
 		src/proto/quickfix.pro \
 		src/proto/regexp.pro \
+		src/proto/register.pro \
 		src/proto/scriptfile.pro \
 		src/proto/screen.pro \
 		src/proto/search.pro \