patch 9.0.0751: 'scrolloff' does not work well with 'smoothscroll'

Problem:    'scrolloff' does not work well with 'smoothscroll'.
Solution:   Make positioning the cursor a bit better.  Rename functions.
diff --git a/src/proto/charset.pro b/src/proto/charset.pro
index c7d5767..0277483 100644
--- a/src/proto/charset.pro
+++ b/src/proto/charset.pro
@@ -15,9 +15,10 @@
 int vim_strsize(char_u *s);
 int vim_strnsize(char_u *s, int len);
 int chartabsize(char_u *p, colnr_T col);
-int linetabsize(char_u *s);
+int linetabsize_str(char_u *s);
 int linetabsize_col(int startcol, char_u *s);
 int win_linetabsize(win_T *wp, linenr_T lnum, char_u *line, colnr_T len);
+int linetabsize(win_T *wp, linenr_T lnum);
 void win_linetabsize_cts(chartabsize_T *cts, colnr_T len);
 int vim_isIDc(int c);
 int vim_isNormalIDc(int c);