Make ppm vhook depend on fork()

Originally committed as revision 9312 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -1667,6 +1667,8 @@ elif check_func dlopen -ldl; then
     ldl=-ldl
 fi
 
+check_func fork
+
 test "$vhook" = "default" && vhook="$dlopen"
 
 enabled_any vhook liba52bin libfaadbin ffserver && add_extralibs $ldl

vhook/Makefile

@@ -6,8 +6,12 @@ CFLAGS=-I$(BUILD_ROOT) -I$(SRC_PATH) -I$(SRC_PATH)/libavutil -I$(SRC_PATH)/libav
        -I$(SRC_PATH)/libavformat -I$(SRC_PATH)/libswscale $(VHOOKCFLAGS) -DHAVE_AV_CONFIG_H
 LDFLAGS+= -g
 
-HOOKS=null$(SLIBSUF) fish$(SLIBSUF) ppm$(SLIBSUF) watermark$(SLIBSUF)
-ALLHOOKS=$(HOOKS) imlib2$(SLIBSUF) drawtext$(SLIBSUF)
+HOOKS=null$(SLIBSUF) fish$(SLIBSUF) watermark$(SLIBSUF)
+ALLHOOKS=$(HOOKS) ppm$(SLIBSUF) imlib2$(SLIBSUF) drawtext$(SLIBSUF)
+
+ifeq ($(HAVE_FORK),yes)
+    HOOKS += ppm$(SLIBSUF)
+endif
 
 ifeq ($(HAVE_IMLIB2),yes)
     HOOKS += imlib2$(SLIBSUF)