Fixed the aux directory to be the one recognized by automake.

This isn't strictly needed by SDL, but it's a good example for other projects.

configure

@@ -2033,7 +2033,7 @@ _ACEOF
 
 
 ac_aux_dir=
-for ac_dir in $srcdir/build-scripts; do
+for ac_dir in build-scripts "$srcdir"/build-scripts; do
   if test -f "$ac_dir/install-sh"; then
     ac_aux_dir=$ac_dir
     ac_install_sh="$ac_aux_dir/install-sh -c"
@@ -2049,8 +2049,8 @@ for ac_dir in $srcdir/build-scripts; do
   fi
 done
 if test -z "$ac_aux_dir"; then
-  { { echo "$as_me:$LINENO: error: cannot find install-sh or install.sh in $srcdir/build-scripts" >&5
-echo "$as_me: error: cannot find install-sh or install.sh in $srcdir/build-scripts" >&2;}
+  { { echo "$as_me:$LINENO: error: cannot find install-sh or install.sh in build-scripts \"$srcdir\"/build-scripts" >&5
+echo "$as_me: error: cannot find install-sh or install.sh in build-scripts \"$srcdir\"/build-scripts" >&2;}
    { (exit 1); exit 1; }; }
 fi
 

configure.in

@@ -2,7 +2,7 @@ dnl Process this file with autoconf to produce a configure script.
 AC_INIT(README)
 AC_CONFIG_HEADER(include/SDL_config.h)
 AC_GNU_SOURCE
-AC_CONFIG_AUX_DIRS($srcdir/build-scripts)
+AC_CONFIG_AUX_DIR(build-scripts)
 AC_CONFIG_MACRO_DIR([acinclude])
 
 dnl Save the CFLAGS to see whether they were passed in or generated