Add more tests for the presence of dlfcn.h and dlopen

Originally committed as revision 1291 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -65,6 +65,8 @@ extralibs="-lm"
 simpleidct="yes"
 bigendian="no"
 vhook="no"
+dlfcn="no"
+dlopen="no"
 mpegaudio_hp="yes"
 SHFLAGS=-shared
 netserver="no"
@@ -181,13 +183,33 @@ ldl=-ldl
 
 if $cc -o $TMPO $TMPC -ldl 2> /dev/null  ; then
 vhook=yes
+dlfcn=yes
+dlopen=yes
 fi
 
 if $cc -o $TMPO $TMPC 2> /dev/null  ; then
 vhook=yes
+dlfcn=yes
+dlopen=yes
 ldl=""
 fi
 
+cat > $TMPC << EOF
+int main( void ) { return (int) dlopen("foo", 0); }
+EOF
+
+if $cc -o $TMPO $TMPC -ldl 2> /dev/null  ; then
+vhook=yes
+dlopen=yes
+fi
+
+if $cc -o $TMPO $TMPC 2> /dev/null  ; then
+vhook=yes
+dlopen=yes
+ldl=""
+fi
+
+
 cat > $TMPC << EOF
 #include <X11/Xlib.h>
 #include <Imlib2.h>
@@ -604,6 +626,14 @@ if test "$v4l" = "yes" ; then
   echo "CONFIG_VIDEO4LINUX=yes" >> config.mak
 fi
 
+if test "$dlopen" = "yes" ; then
+  echo "#define CONFIG_HAVE_DLOPEN 1" >> $TMPH
+fi
+
+if test "$dlfcn" = "yes" ; then
+  echo "#define CONFIG_HAVE_DLFCN 1" >> $TMPH
+fi
+
 if test "$audio_oss" = "yes" ; then
   echo "#define CONFIG_AUDIO_OSS 1" >> $TMPH
   echo "CONFIG_AUDIO_OSS=yes" >> config.mak