Requiring autoconf's AC_FUNC_STRERROR_R and then calling AC_DEFINE
ourselves leads to two insertions of #define STRERROR_R_CHAR_P
in confdefs.h, but with different values (at least on glibc). This
in turn sparks a gcc warning about redeclaring the macro, and kills
any subsequent tests that use -Werror (which now error because of
the conflicting define, whether or not the test used to error).
A better approach is to replace the autoconf macro with a version
of our own that doesn't probe anything, so that the AC_DEFINE is
reached exactly once.
* m4/strerror_r.m4 (AC_FUNC_STRERROR_R): New override.
(gl_FUNC_STRERROR_R): Don't reuse AC_DEFINE() with a potentially
different value.
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
ChangeLog | 7 +++++++
m4/strerror_r.m4 | 13 ++++++++++---
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index e5d7987..4837fe2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-11-04 Eric Blake <ebl...@redhat.com>
+
+ strerror_r-posix: Fix override of AC_FUNC_STRERROR_R
+ * m4/strerror_r.m4 (AC_FUNC_STRERROR_R): New override.
+ (gl_FUNC_STRERROR_R): Don't reuse AC_DEFINE() with a potentially
+ different value.
+
2016-11-03 Eric Blake <ebl...@redhat.com>
bootstrap: Fix get_version() for AIX 5.3
diff --git a/m4/strerror_r.m4 b/m4/strerror_r.m4
index 06c51e1..c566f38 100644
--- a/m4/strerror_r.m4
+++ b/m4/strerror_r.m4
@@ -1,4 +1,4 @@
-# strerror_r.m4 serial 16
+# strerror_r.m4 serial 17
dnl Copyright (C) 2002, 2007-2016 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -41,8 +41,15 @@ AC_DEFUN([gl_FUNC_STRERROR_R],
# Overwrite the findings of AC_FUNC_STRERROR_R (for code that uses that).
AC_REQUIRE([AC_FUNC_STRERROR_R])
- AC_DEFINE([HAVE_DECL_STRERROR_R], [1])
- AC_DEFINE([STRERROR_R_CHAR_P], [0])
+])
+
+# If this module is in use, we unconditionally want POSIX semantics; so
+# replace autoconf's macro with a version that does not probe
+AC_DEFUN([AC_FUNC_STRERROR_R], [
+ AC_DEFINE([HAVE_DECL_STRERROR_R], [1],
+ [Define to 1, since you should have the declaration of strerror_r.])
+ AC_DEFINE([STRERROR_R_CHAR_P], [0],
+ [Define to 0, since strerror_r should not return char *.])
])
# Prerequisites of lib/strerror_r.c.
--
2.7.4
