Our ALSA code needs alloca, so check for it in configure and include alloca.h

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@27313 b3059339-0415-0410-9bf9-f77b7e298cf2

configure

@@ -5205,6 +5205,10 @@ fi
 echores "$_openal"
 
 echocheck "ALSA audio"
+if test "$_alloca" != yes ; then
+  _alsa=no
+  _res_comment="alloca missing"
+fi
 if test "$_alsa" != no ; then
   _alsa=no
   cat > $TMPC << EOF

libao2/ao_alsa.c

@@ -19,6 +19,7 @@
 #include <ctype.h>
 #include <math.h>
 #include <string.h>
+#include <alloca.h>
 
 #include "config.h"
 #include "subopt-helper.h"

stream/ai_alsa.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/time.h>
+#include <alloca.h>
 
 #include "config.h"
 

stream/ai_alsa1x.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/time.h>
+#include <alloca.h>
 
 #include "config.h"