'…' ellipsis character is garbled under MSVC

[noscript]

Problem:  Source code is not treated as utf-8 by MSVC, so '…'
          character in string literal is interpreted wrong.
Solution: Replace '…' in source code with octal escape sequence.

Example of breakage https://github.com/noscript/vim/actions/runs/29205020293/attempts/1:

Expected
['foo                 ', 'some long virtual t…', '~                   ']
but got
['foo                 ', 'some long virtua�   ', '~                   ']

where "…" is not interpreted properly and its byte length is also wrong, causing garbage in rendering.

The problem is probably bigger than the fix addresses, but I don't have Windows environment and have no opportunity to experiment.

[h-east]

Problem:  Source code is not treated as utf-8 by MSVC, so '…'
          character in string literal is interpreted wrong.

Hmm? The file displays correctly in VS Code.

I don't think this is the right solution.
Isn't it possible that some other issue is causing this?

[noscript]

It's not about displaying the source code. I suppose if you run the portion of the test in vim compiled by MSVC, you should also see garbage when virtual text is trimmed with ellipsis.

Maybe MSVC needs some flag to treat source files as utf-8, I am not really sure.

[k-takata]

Does this solve the issue (without changing "…" to "\342\200\246")?

--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -537,7 +537,7 @@ CFLAGS = -c /W3 /GF /nologo -I. -Iproto -DHAVE_PATHDEF -DWIN32 -DHAVE_STDINT_H \
        $(CSCOPE_DEFS) $(TERM_DEFS) $(SOUND_DEFS) $(NETBEANS_DEFS) \
        $(NBDEBUG_DEFS) $(XPM_DEFS) $(SOD_DEFS) $(SOD_INC) $(CHANNEL_DEFS) \
        $(DEFINES) $(CI_CFLAGS) -DWINVER=$(WINVER) -D_WIN32_WINNT=$(WINVER) \
-       /source-charset:utf-8
+       /utf-8
 
 RCFLAGS = -DVIM_VERSION_PATCHLEVEL=$(PATCHLEVEL)
 

Currently, source-charset is set to utf-8, but execution-charset is not.
Changing it may solve the issue, but may cause another.

[noscript]

Changing it may solve the issue, but may cause another.

Thank you for the fix, at least CI passes.

[chrisbra]

Thanks. Let me include it. Since CI is green I hope it won't cause any issues for Windows users.