Thanks for reporting that. I installed the attached patch to work around
the bug in libpng. Of course this is just a hack, but there's some
benefit to it and no harm that I can see.
Could you please report the issue to the libpng maintainers? The
attached second patch should work around the immediate issue for them. I
am not plugged into the libpng ecosystem and don't know how to send them
bug reports. Thanks.From 078edd8c0fb36b0245df3c6ebd621225dea9b685 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@xxxxxxxxxxx>
Date: Wed, 16 Nov 2022 10:19:43 -0800
Subject: [PATCH] Cater better to underquoted callers
Problem reported by Frederic Berat in:
https://lists.gnu.org/r/autoconf/2022-11/msg00092.html
* lib/autoconf/c.m4 (AC_LANG_CALL(C)): Omit comma in comment,
which triggers bugs in underquoted callers.
---
lib/autoconf/c.m4 | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
index 5e4301e7..a388599c 100644
--- a/lib/autoconf/c.m4
+++ b/lib/autoconf/c.m4
@@ -128,7 +128,7 @@ m4_if([$2], [main], ,
Use char because int might match the return type of a GCC
builtin and then its argument prototype would still apply.
The 'extern "C"' is for builds by C++ compilers;
- although this is not generally supported in C code, supporting it here
+ although this is not generally supported in C code supporting it here
has little cost and some practical benefit (sr 110532). */
#ifdef __cplusplus
extern "C"
--
2.37.2
diff --git a/configure.ac b/configure.ac
index 58dddd80a..a553f8a91 100644
--- a/configure.ac
+++ b/configure.ac
@@ -138,7 +138,8 @@ AC_STRUCT_TM
AC_C_RESTRICT
# Checks for library functions.
-AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_MSG_ERROR(cannot find pow)))
+AC_CHECK_FUNCS([pow], ,
+ [AC_CHECK_LIB([m], [pow], , [AC_MSG_ERROR([cannot find pow])])])
# Some later POSIX 1003.1 functions are required for test programs, failure
# here is soft (the corresponding test program is not built).
@@ -150,8 +151,9 @@ AC_ARG_WITH(zlib-prefix,
[prefix that may have been used in installed zlib]),
[ZPREFIX=${withval}],
[ZPREFIX='z_'])
-AC_CHECK_LIB(z, zlibVersion, ,
- AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, , AC_MSG_ERROR(zlib not installed)))
+AC_CHECK_LIB([z], [zlibVersion], ,
+ [AC_CHECK_LIB([z], [${ZPREFIX}zlibVersion], ,
+ [AC_MSG_ERROR([zlib not installed])])])
# The following is for pngvalid, to ensure it catches FP errors even on
# platforms that don't enable FP exceptions, the function appears in the math
