avformat/avisynth.c: Use new safe dlopen code.

Signed-off-by: Matt Oliver <protogonoi@gmail.com>

configure

@@ -2753,6 +2753,9 @@ ac3_at_decoder_select="ac3_parser"
 adpcm_ima_qt_at_decoder_deps="audiotoolbox"
 alac_at_decoder_deps="audiotoolbox"
 amr_nb_at_decoder_deps="audiotoolbox"
+avisynth_deps_any="dlopen LoadLibrary"
+avisynth_demuxer_deps="avisynth"
+avisynth_demuxer_select="riffdec"
 eac3_at_decoder_deps="audiotoolbox"
 eac3_at_decoder_select="ac3_parser"
 gsm_ms_at_decoder_deps="audiotoolbox"
@@ -2846,8 +2849,6 @@ asf_muxer_select="riffenc"
 asf_stream_muxer_select="asf_muxer"
 avi_demuxer_select="iso_media riffdec exif"
 avi_muxer_select="riffenc"
-avisynth_demuxer_deps="avisynth"
-avisynth_demuxer_select="riffdec"
 caf_demuxer_select="iso_media riffdec"
 dash_muxer_select="mp4_muxer"
 dirac_demuxer_select="dirac_parser"
@@ -5414,6 +5415,7 @@ elif check_func dlopen -ldl && check_func dlsym -ldl; then
     ldl=-ldl
 fi
 
+avisynth_demuxer_extralibs='$ldl'
 decklink_outdev_extralibs="$decklink_outdev_extralibs $ldl"
 decklink_indev_extralibs="$decklink_indev_extralibs $ldl"
 frei0r_filter_extralibs='$ldl'
@@ -5661,9 +5663,6 @@ fi
 enabled avfoundation_indev && { check_header_objcc AVFoundation/AVFoundation.h || disable avfoundation_indev; }
 enabled avfoundation_indev && { check_lib2 CoreGraphics/CoreGraphics.h CGGetActiveDisplayList -framework CoreGraphics ||
                                 check_lib2 ApplicationServices/ApplicationServices.h CGGetActiveDisplayList -framework ApplicationServices; }
-enabled avisynth          && { { check_lib2 "windows.h" LoadLibrary; } ||
-                               { check_lib2 "dlfcn.h" dlopen -ldl; } ||
-                               die "ERROR: LoadLibrary/dlopen not found for avisynth"; }
 enabled cuda              && { check_lib cuda.h cuInit -lcuda ||
                                die "ERROR: CUDA not found"; }
 enabled cuvid             && { add_cflags -I$source_path;

libavformat/Makefile

@@ -106,7 +106,7 @@ OBJS-$(CONFIG_AU_DEMUXER)                += au.o pcm.o
 OBJS-$(CONFIG_AU_MUXER)                  += au.o rawenc.o
 OBJS-$(CONFIG_AVI_DEMUXER)               += avidec.o
 OBJS-$(CONFIG_AVI_MUXER)                 += avienc.o mpegtsenc.o avlanguage.o rawutils.o
-OBJS-$(CONFIG_AVISYNTH)                  += avisynth.o
+OBJS-$(CONFIG_AVISYNTH_DEMUXER)          += avisynth.o
 OBJS-$(CONFIG_AVM2_MUXER)                += swfenc.o swf.o
 OBJS-$(CONFIG_AVR_DEMUXER)               += avr.o pcm.o
 OBJS-$(CONFIG_AVS_DEMUXER)               += avs.o voc_packet.o vocdec.o voc.o

libavformat/avisynth.c

@@ -29,7 +29,7 @@
 
 /* Platform-specific directives for AviSynth vs AvxSynth. */
 #ifdef _WIN32
-  #include <windows.h>
+  #include "compat/w32dlfcn.h"
   #undef EXTERN_C
   #include "compat/avisynth/avisynth_c.h"
   #define AVISYNTH_LIB "avisynth"
@@ -39,10 +39,6 @@
   #include "compat/avisynth/avxsynth_c.h"
   #define AVISYNTH_NAME "libavxsynth"
   #define AVISYNTH_LIB AVISYNTH_NAME SLIBSUF
-
-  #define LoadLibrary(x) dlopen(x, RTLD_NOW | RTLD_LOCAL)
-  #define GetProcAddress dlsym
-  #define FreeLibrary dlclose
 #endif
 
 typedef struct AviSynthLibrary {
@@ -118,13 +114,13 @@ static av_cold void avisynth_atexit_handler(void);
 
 static av_cold int avisynth_load_library(void)
 {
-    avs_library.library = LoadLibrary(AVISYNTH_LIB);
+    avs_library.library = dlopen(AVISYNTH_LIB, RTLD_NOW | RTLD_LOCAL);
     if (!avs_library.library)
         return AVERROR_UNKNOWN;
 
 #define LOAD_AVS_FUNC(name, continue_on_fail)                          \
         avs_library.name =                                             \
-            (void *)GetProcAddress(avs_library.library, #name);        \
+            (void *)dlsym(avs_library.library, #name);                 \
         if (!continue_on_fail && !avs_library.name)                    \
             goto fail;
 
@@ -157,7 +153,7 @@ static av_cold int avisynth_load_library(void)
     return 0;
 
 fail:
-    FreeLibrary(avs_library.library);
+    dlclose(avs_library.library);
     return AVERROR_UNKNOWN;
 }
 
@@ -225,7 +221,7 @@ static av_cold void avisynth_atexit_handler(void)
         avisynth_context_destroy(avs);
         avs = next;
     }
-    FreeLibrary(avs_library.library);
+    dlclose(avs_library.library);
 
     avs_atexit_called = 1;
 }