From: Matt Jolly <kangie@gentoo.org>
Date: Thu, 30 May 2024 04:47:11 +0000 (+1000)
Subject: autoconf: remove 'deeper' checks for `AC_CHECK_FUNCS`
X-Git-Tag: curl-8_9_0~343
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=beff006a8eecc5fc3495badae209791eb779414d;p=thirdparty%2Fcurl.git

autoconf: remove 'deeper' checks for `AC_CHECK_FUNCS`

The net effect of the deeper checks is to raise implicit function decls
on modern compilers.

These checks appear to have been added ~20 years ago, relating to an
unverifiable claim about HP-UX. Autoconf support for the platform has
grown in leaps and bounds since.

It didn't cause a real problem here, but when investigating a FP this
came up. No evidence has been identified that this was actually broken
in the past, and there is no evidence that this is necessary now.

`-Werror=implicit-function-declarations` is enabled for both checks;
without a working prototype they will both fail regardless. In the
second case there will in fact never be a working prototype and
therefore it will always fail unconditionally.

`AC_CHECK_FUNCS` does effectively the same thing as the removed checks,
except it actually defines a dummy prototype to see if it links.

If `AC_CHECK_FUNCS` is broken on a given platform we have bigger
problems than trying to build cURL. This should also be faster.

Bug: https://bugs.gentoo.org/932827
Reviewed-By: Eli Schwartz <eschwartz93@gmail.com>
Closes #13830
---

diff --git a/configure.ac b/configure.ac
index 85f0ab599b..57c57741b6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3800,26 +3800,6 @@ AC_CHECK_FUNCS([\
   snprintf \
   utime \
   utimes \
-],[
-],[
-  func="$ac_func"
-  eval skipcheck=\$skipcheck_$func
-  if test "x$skipcheck" != "xyes"; then
-    AC_MSG_CHECKING([deeper for $func])
-    AC_LINK_IFELSE([
-      AC_LANG_PROGRAM([[
-      ]],[[
-        $func ();
-      ]])
-    ],[
-      AC_MSG_RESULT([yes])
-      eval "ac_cv_func_$func=yes"
-      AC_DEFINE_UNQUOTED(XC_SH_TR_CPP([HAVE_$func]), [1],
-        [Define to 1 if you have the $func function.])
-    ],[
-      AC_MSG_RESULT([but still no])
-    ])
-  fi
 ])
 
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