Compiling GNU poke 3.90.2 on FreeBSD 12.2/sparc64, I see several of these
warnings:
In file included from ../../jitter/jitterc/jitterc-generate.h:27,
from ../../jitter/jitterc/jitterc-generate.c:38:
./config-private/config.h:1801:1: warning: "_GL_HAS_ATTRIBUTE" redefined
In file included from ../../jitter/jitterc/jitterc-generate.c:23:
./config-private/config.h:1803:1: warning: this is the location of the previous
definition
The problem is that
- config.h is included more than once,
- upon 1st inclusion, __has_attribute is not defined, because the compiler
is gcc < 5,
- then <sys/cdefs.h> gets included, which defines __has_attribute:
#ifndef __has_attribute
#define __has_attribute(x) 0
#endif
- then config.h is included again, and now this definition of
_GL_HAS_ATTRIBUTE is used:
#if (defined __has_attribute \
&& (!defined __clang_minor__ \
|| (defined __apple_build_version__ \
? 6000000 <= __apple_build_version__ \
: 5 <= __clang_major__)))
# define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
#else
Thus a wrong definition of _GL_HAS_ATTRIBUTE prevails, that turns off all
attributes.
This patch fixes it.
2024-02-09 Bruno Haible <br...@clisp.org>
Avoid suboptimal definition of _GL_HAS_ATTRIBUTE on FreeBSD/sparc64.
* m4/gnulib-common.m4 (gl_COMMON_BODY): Define _GL_HAS_ATTRIBUTE only
once.
diff -w --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4
index 00691c0d6c..d8d0904f78 100644
--- a/m4/gnulib-common.m4
+++ b/m4/gnulib-common.m4
@@ -1,4 +1,4 @@
-# gnulib-common.m4 serial 91
+# gnulib-common.m4 serial 92
dnl Copyright (C) 2007-2024 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -76,6 +76,11 @@ AC_DEFUN([gl_COMMON_BODY]
#endif])
AH_VERBATIM([attribute],
[/* Attributes. */
+/* Define _GL_HAS_ATTRIBUTE only once, because on FreeBSD, with gcc < 5, if
+ <config.h> gets included once again after <sys/cdefs.h>, __has_attribute(x)
+ expands to 0 always, and redefining _GL_HAS_ATTRIBUTE would turn off all
+ attributes. */
+#ifndef _GL_HAS_ATTRIBUTE
# if (defined __has_attribute \
&& (!defined __clang_minor__ \
|| (defined __apple_build_version__ \
@@ -113,6 +118,7 @@ AC_DEFUN([gl_COMMON_BODY]
# define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7)
# define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4)
# endif
+#endif
/* Use __has_c_attribute if available. However, do not use with
pre-C23 GCC, which can issue false positives if -Wpedantic. */
