configure: remove support for "embedded ares"

In March 2010 (commit 4259d2df7dd) we removed the embedded 'ares'
directory from the curl source tree but we have since supported
especially detecting and using that build directory. The time has come
to remove that kludge and ask users to specify the c-ares dir correctly
with --enable-ares.

Closes #8397

1 files changed, 42 insertions, 57 deletions

diff --git a/m4/curl-confopts.m4 b/m4/curl-confopts.m4
index efe42495d..588da7dd9 100644
--- a/m4/curl-confopts.m4
+++ b/m4/curl-confopts.m4
@@ -5,7 +5,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -487,9 +487,7 @@ AC_DEFUN([CURL_CHECK_LIB_ARES], [
     clean_CPPFLAGS="$CPPFLAGS"
     clean_LDFLAGS="$LDFLAGS"
     clean_LIBS="$LIBS"
-    embedded_ares="unknown"
     configure_runpath=`pwd`
-    embedded_ares_builddir="$configure_runpath/ares"
     if test -n "$want_ares_path"; then
       dnl c-ares library path has been specified
       ARES_PCDIR="$want_ares_path/lib/pkgconfig"
@@ -511,31 +509,19 @@ AC_DEFUN([CURL_CHECK_LIB_ARES], [
         ares_LIBS="-lcares"
       fi
     else
-      dnl c-ares library path has not been given
-      if test -d "$srcdir/ares"; then
-        dnl c-ares sources embedded in curl tree
-        embedded_ares="yes"
-        AC_CONFIG_SUBDIRS(ares)
-        dnl c-ares has installable configured header files, path
-        dnl inclusion fully done in makefiles for in-tree builds.
+      dnl c-ares path not specified, use defaults
+      CURL_CHECK_PKGCONFIG(libcares)
+      if test "$PKGCONFIG" != "no" ; then
+        ares_LIBS=`$PKGCONFIG --libs-only-l libcares`
+        ares_LDFLAGS=`$PKGCONFIG --libs-only-L libcares`
+        ares_CPPFLAGS=`$PKGCONFIG --cflags-only-I libcares`
+        AC_MSG_NOTICE([pkg-config: ares_LIBS: "$ares_LIBS"])
+        AC_MSG_NOTICE([pkg-config: ares_LDFLAGS: "$ares_LDFLAGS"])
+        AC_MSG_NOTICE([pkg-config: ares_CPPFLAGS: "$ares_CPPFLAGS"])
+      else
         ares_CPPFLAGS=""
-        ares_LDFLAGS="-L$embedded_ares_builddir"
+        ares_LDFLAGS=""
         ares_LIBS="-lcares"
-      else
-        dnl c-ares path not specified, use defaults
-        CURL_CHECK_PKGCONFIG(libcares)
-        if test "$PKGCONFIG" != "no" ; then
-          ares_LIBS=`$PKGCONFIG --libs-only-l libcares`
-          ares_LDFLAGS=`$PKGCONFIG --libs-only-L libcares`
-          ares_CPPFLAGS=`$PKGCONFIG --cflags-only-I libcares`
-          AC_MSG_NOTICE([pkg-config: ares_LIBS: "$ares_LIBS"])
-          AC_MSG_NOTICE([pkg-config: ares_LDFLAGS: "$ares_LDFLAGS"])
-          AC_MSG_NOTICE([pkg-config: ares_CPPFLAGS: "$ares_CPPFLAGS"])
-        else
-          ares_CPPFLAGS=""
-          ares_LDFLAGS=""
-          ares_LIBS="-lcares"
-        fi
       fi
     fi
     #
@@ -543,38 +529,37 @@ AC_DEFUN([CURL_CHECK_LIB_ARES], [
     LDFLAGS="$clean_LDFLAGS $ares_LDFLAGS"
     LIBS="$ares_LIBS $clean_LIBS"
     #
-    if test "$embedded_ares" != "yes"; then
-      dnl check if c-ares new enough when not using an embedded
-      dnl source tree one which normally has not been built yet.
-      AC_MSG_CHECKING([that c-ares is good and recent enough])
-      AC_LINK_IFELSE([
-        AC_LANG_PROGRAM([[
+
+    dnl check if c-ares new enough
+    AC_MSG_CHECKING([that c-ares is good and recent enough])
+    AC_LINK_IFELSE([
+      AC_LANG_PROGRAM([[
 #include <ares.h>
-          /* set of dummy functions in case c-ares was built with debug */
-          void curl_dofree() { }
-          void curl_sclose() { }
-          void curl_domalloc() { }
-          void curl_docalloc() { }
-          void curl_socket() { }
-        ]],[[
-          ares_channel channel;
-          ares_cancel(channel); /* added in 1.2.0 */
-          ares_process_fd(channel, 0, 0); /* added in 1.4.0 */
-          ares_dup(&channel, channel); /* added in 1.6.0 */
-        ]])
-      ],[
-        AC_MSG_RESULT([yes])
-      ],[
-        AC_MSG_RESULT([no])
-        AC_MSG_ERROR([c-ares library defective or too old])
-        dnl restore initial settings
-        CPPFLAGS="$clean_CPPFLAGS"
-        LDFLAGS="$clean_LDFLAGS"
-        LIBS="$clean_LIBS"
-        # prevent usage
-        want_ares="no"
-      ])
-    fi
+        /* set of dummy functions in case c-ares was built with debug */
+        void curl_dofree() { }
+        void curl_sclose() { }
+        void curl_domalloc() { }
+        void curl_docalloc() { }
+        void curl_socket() { }
+      ]],[[
+        ares_channel channel;
+        ares_cancel(channel); /* added in 1.2.0 */
+        ares_process_fd(channel, 0, 0); /* added in 1.4.0 */
+        ares_dup(&channel, channel); /* added in 1.6.0 */
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+    ],[
+      AC_MSG_RESULT([no])
+      AC_MSG_ERROR([c-ares library defective or too old])
+      dnl restore initial settings
+      CPPFLAGS="$clean_CPPFLAGS"
+      LDFLAGS="$clean_LDFLAGS"
+      LIBS="$clean_LIBS"
+      # prevent usage
+      want_ares="no"
+    ])
+
     if test "$want_ares" = "yes"; then
       dnl finally c-ares will be used
       AC_DEFINE(USE_ARES, 1, [Define to enable c-ares support])