37 lines
1.2 KiB
Diff
37 lines
1.2 KiB
Diff
From b27bc3e230bb12fdd9a813e38e82bc4c3e22b4cc Mon Sep 17 00:00:00 2001
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From: Paul Eggert <eggert@cs.ucla.edu>
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Date: Tue, 31 Aug 2021 16:30:46 -0700
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Subject: [PATCH] Port AC_LANG_CALL(C) to C++
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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* lib/autoconf/c.m4 (AC_LANG_CALL(C)): Add an extern "C" if C++.
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Problem reported by Vincent Lefèvre (sr #110532).
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---
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lib/autoconf/c.m4 | 8 +++++++-
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1 file changed, 7 insertions(+), 1 deletion(-)
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diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
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index 44443a39..48bd49a3 100644
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--- a/lib/autoconf/c.m4
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+++ b/lib/autoconf/c.m4
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@@ -126,7 +126,13 @@ m4_define([AC_LANG_CALL(C)],
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m4_if([$2], [main], ,
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[/* Override any GCC internal prototype to avoid an error.
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Use char because int might match the return type of a GCC
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- builtin and then its argument prototype would still apply. */
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+ builtin and then its argument prototype would still apply.
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+ The 'extern "C"' is for builds by C++ compilers;
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+ although this is not generally supported in C code, supporting it here
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+ has little cost and some practical benefit (sr 110532). */
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+#ifdef __cplusplus
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+extern "C"
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+#endif
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char $2 ();])], [return $2 ();])])
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--
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2.43.5
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