SDL: bump minimum required autoconf version and revise autogen.sh

From babd79b8efec2bb379781c159f026ac0f62f7004 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Wed, 14 Apr 2021 23:20:40 +0300
Subject: [PATCH] bump minimum required autoconf version and revise autogen.sh

---
 autogen.sh      | 18 +++++++++---------
 configure.ac    |  2 +-
 test/autogen.sh | 17 ++++++++---------
 3 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/autogen.sh b/autogen.sh
index 9edfb8a7d..daf160de5 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-#
+
 echo "Generating build information using autoconf"
 echo "This may take a while ..."
 
@@ -9,15 +9,15 @@ cd "$srcdir"
 
 # Regenerate configuration files
 cat acinclude/* >aclocal.m4
-found=false
-for autoconf in autoconf autoconf259 autoconf-2.59
-do if which $autoconf >/dev/null 2>&1; then $autoconf && found=true; break; fi
-done
-if test x$found = xfalse; then
-    echo "Couldn't find autoconf, aborting"
-    exit 1
+
+if test "$AUTOCONF"x = x; then
+  AUTOCONF=autoconf
 fi
+
+$AUTOCONF || exit 1
+rm aclocal.m4
+rm -rf autom4te.cache
+
 (cd test; sh autogen.sh)
 
-# Run configure for this platform
 echo "Now you are ready to run ./configure"
diff --git a/configure.ac b/configure.ac
index 33dcd5a80..b6783a080 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-AC_PREREQ([2.59])
+AC_PREREQ([2.63])
 AC_INIT
 AC_CONFIG_SRCDIR([src/SDL.c])
 AC_CONFIG_HEADERS([include/SDL_config.h])
diff --git a/test/autogen.sh b/test/autogen.sh
index 939f34c0f..988d41760 100755
--- a/test/autogen.sh
+++ b/test/autogen.sh
@@ -1,12 +1,11 @@
 #!/bin/sh
-#
-# Regenerate configuration files
+
 cp acinclude.m4 aclocal.m4
-found=false
-for autoconf in autoconf autoconf259 autoconf-2.59
-do if which $autoconf >/dev/null 2>&1; then $autoconf && found=true; break; fi
-done
-if test x$found = xfalse; then
-    echo "Couldn't find autoconf, aborting"
-    exit 1
+
+if test "$AUTOCONF"x = x; then
+  AUTOCONF=autoconf
 fi
+
+$AUTOCONF || exit 1
+rm aclocal.m4
+rm -rf autom4te.cache