acinclude & sdl2.m4 updates:

- acinclude/alsa.m4, esd.m4: Ran through autoupdate to replace several
  AC_TRY_[COMPILE|LINK|RUN] with corresponding AC_???_IFELSE , so that
  autoconf-2.70 doesn't warn.
- sdl2.m4: Ditto.
- test/acinclude.m4 (sdl2): Ditto.

acinclude/alsa.m4

@@ -72,11 +72,10 @@ no_alsa=""
     alsa_min_micro_version=`echo $min_alsa_version | \
            sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\3/'`
 
-AC_LANG_SAVE
-AC_LANG_C
-AC_TRY_COMPILE([
+AC_LANG_PUSH([C])
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 #include <alsa/asoundlib.h>
-], [
+]], [[
 /* ensure backward compatibility */
 #if !defined(SND_LIB_MAJOR) && defined(SOUNDLIB_VERSION_MAJOR)
 #define SND_LIB_MAJOR SOUNDLIB_VERSION_MAJOR
@@ -108,13 +107,13 @@ AC_TRY_COMPILE([
 #    endif
 #  endif
 exit(0);
-],
+]])],
   [AC_MSG_RESULT(found.)],
   [AC_MSG_RESULT(not present.)
    ifelse([$3], , [AC_MSG_ERROR(Sufficiently new version of libasound not found.)])
    alsa_found=no]
 )
-AC_LANG_RESTORE
+AC_LANG_POP([C])
 
 dnl Now that we know that we have the right version, let's see if we have the library and not just the headers.
 if test "x$enable_alsatest" = "xyes"; then

acinclude/esd.m4

@@ -58,7 +58,7 @@ dnl Now check if the installed ESD is sufficiently new. (Also sanity
 dnl checks the results of esd-config to some extent
 dnl
       rm -f conf.esdtest
-      AC_TRY_RUN([
+      AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <stdio.h>
 #include <stdlib.h>
 #include <esd.h>
@@ -92,7 +92,7 @@ int main (void)
       return 1;
     }
 }
-], [], [no_esd=yes], [echo $ac_n "cross compiling; assumed OK... $ac_c"])
+]])], [], [no_esd=yes], [echo $ac_n "cross compiling; assumed OK... $ac_c"])
        CFLAGS="$ac_save_CFLAGS"
        LIBS="$ac_save_LIBS"
        AC_LANG_POP([C])
@@ -116,10 +116,10 @@ int main (void)
           CFLAGS="$CFLAGS $ESD_CFLAGS"
           LIBS="$LIBS $ESD_LIBS"
           AC_LANG_PUSH([C])
-          AC_TRY_LINK([
+          AC_LINK_IFELSE([AC_LANG_PROGRAM([[
 #include <stdio.h>
 #include <esd.h>
-],      [ return 0; ],
+]], [[ return 0; ]])],
         [ echo "*** The test program compiled, but did not run. This usually means"
           echo "*** that the run-time linker is not finding ESD or finding the wrong"
           echo "*** version of ESD. If it is not finding ESD, you'll need to set your"