mcel: Fix compilation error with MSVC

[Bruno Haible]

A testdir of
  mbscasestr mcel-prefer
when build with MSVC, produces link errors:

libgnu.a(mbscasestr.obj) : error LNK2019: unresolved external symbol 
__builtin_expect referenced in function mcel_tocmp
libgnu.a(mbslen.obj) : error LNK2001: unresolved external symbol 
__builtin_expect
test-mbscasestr1.exe : fatal error LNK1120: 1 unresolved externals
make[4]: *** [Makefile:5079: test-mbscasestr1.exe] Error 2

The reason is that mcel.h uses __builtin_expect, but __builtin_expect is
not defined. This patch fixes it.


2024-08-27  Bruno Haible  <bruno@clisp.org>

        mcel: Fix compilation error with MSVC.
        * modules/builtin-expect (Description): Improve.
        * m4/builtin-expect.m4: Improve comment.
        * modules/mcel (Depends-on): Add builtin-expect.

diff --git a/m4/builtin-expect.m4 b/m4/builtin-expect.m4
index c7af926b34..33f255e9f5 100644
--- a/m4/builtin-expect.m4
+++ b/m4/builtin-expect.m4
@@ -1,11 +1,11 @@
 # builtin-expect.m4
-# serial 1
+# serial 2
 dnl Copyright 2016-2024 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-dnl Check for __builtin_expect.
+dnl Provide a GCC-compatible __builtin_expect macro in <config.h>.
 
 dnl Written by Paul Eggert.
 
diff --git a/modules/builtin-expect b/modules/builtin-expect
index c11d5d96c9..489a16894d 100644
--- a/modules/builtin-expect
+++ b/modules/builtin-expect
@@ -1,5 +1,5 @@
 Description:
-Check for __builtin_expect.
+Provide a GCC-compatible __builtin_expect macro.
 
 Files:
 m4/builtin-expect.m4
diff --git a/modules/mcel b/modules/mcel
index 59ca633641..4bdde8f95a 100644
--- a/modules/mcel
+++ b/modules/mcel
@@ -7,6 +7,7 @@ lib/mcel.h
 
 Depends-on:
 assert-h
+builtin-expect
 extern-inline
 limits-h
 mbrtoc32