Disable threading support by default on all platforms, add individual

enabling options and hook this up in configure output.
patch by Ramiro Polla, ramiro lisha.ufsc br

Originally committed as revision 7420 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -71,6 +71,8 @@ show_help(){
   echo "  --enable-pp              enable GPLed postprocessing support [default=no]"
   echo "  --enable-swscaler        software scaler support [default=no]"
   echo "  --enable-sunmlib         use Sun medialib [default=no]"
+  echo "  --enable-beosthreads     use BeOS threads [default=no]"
+  echo "  --enable-os2threads      use OS/2 threads [default=no]"
   echo "  --enable-pthreads        use pthreads [default=no]"
   echo "  --enable-w32threads      use Win32 threads [default=no]"
   echo "  --enable-x11grab         enable X11 grabbing [default=no]"
@@ -648,8 +650,11 @@ amr_wb="no"
 amr_nb_fixed="no"
 amr_if2="no"
 mlib="no"
+beosthreads="no"
+os2threads="no"
 pthreads="no"
 w32threads="no"
+thread_type="no"
 swscaler="no"
 gpl="no"
 memalign_hack="no"
@@ -681,7 +686,6 @@ video4linux2="no"
 dv1394="no"
 # enable BeOS things
 audio_beos="yes"
-beosthreads="yes"
 # no need for libm, but the inet stuff
 # Check for BONE
 if (echo $BEINCLUDES|grep 'headers/be/bone' >/dev/null); then
@@ -829,7 +833,6 @@ dv1394="no"
 ffserver="no"
 vhook="no"
 os2="yes"
-os2threads="yes"
 ;;
 *)
 targetos="${targetos}-UNKNOWN"
@@ -1017,6 +1020,10 @@ for opt do
   ;;
   --enable-w32threads) w32threads="yes"
   ;;
+  --enable-beosthreads) beosthreads="yes"
+  ;;
+  --enable-os2threads) os2threads="yes"
+  ;;
   --enable-swscaler) swscaler="yes"
   ;;
   --enable-gpl) gpl="yes"
@@ -1462,6 +1469,16 @@ if enabled pthreads; then
     fi
 fi
 
+for thread in pthreads beosthreads os2threads w32threads; do
+    if enabled $thread; then
+        if test $thread_type != "no"; then
+            die "ERROR: Only one thread type must be selected."
+        else
+            thread_type="$thread"
+        fi
+    fi
+done
+
 # these are off by default, so fail if requested and not available
 enabled libdts  && require libdts dts.h dts_init -ldts -lm
 enabled libgsm  && require libgsm gsm.h gsm_create -lgsm
@@ -1785,7 +1802,7 @@ echo "network support           $network"
 if test "$network" = "yes" ; then
     echo "IPv6 support              $ipv6"
 fi
-echo "pthreads support          $pthreads"
+echo "threading support         $thread_type"
 echo "SDL support               $sdl"
 if test $sdl_too_old = "yes"; then
     echo "-> Your SDL version is too old - please upgrade to have FFplay/SDL support."