configure.patch

--- /tmp/ffmpeg-4.1/configure
+++ /tmp/ffmpeg-4.1-src/configure
@@ -215,6 +215,7 @@
   --enable-gnutls          enable gnutls, needed for https support
                            if openssl, libtls or mbedtls is not used [no]
   --disable-iconv          disable iconv [autodetect]
+  --enable-vfw             enable VFW(for lagarith) support [no]
   --enable-jni             enable JNI support [no]
   --enable-ladspa          enable LADSPA audio filtering [no]
   --enable-libaom          enable AV1 video encoding/decoding via libaom [no]
@@ -1761,6 +1762,7 @@
     openal
     opengl
     vapoursynth
+	vfw
 "
 
 HWACCEL_AUTODETECT_LIBRARY_LIST="
@@ -2668,6 +2670,7 @@
 jpegls_decoder_select="mjpeg_decoder"
 jv_decoder_select="blockdsp"
 lagarith_decoder_select="llviddsp"
+lagarith_encoder_deps="vfw"
 ljpeg_encoder_select="idctdsp jpegtables mpegvideoenc"
 magicyuv_decoder_select="llviddsp"
 magicyuv_encoder_select="llvidencdsp"
@@ -6049,6 +6052,7 @@
 # these are off by default, so fail if requested and not available
 enabled cuda_sdk          && require cuda_sdk cuda.h cuCtxCreate -lcuda
 enabled chromaprint       && require chromaprint chromaprint.h chromaprint_get_version -lchromaprint
+enabled vfw               && add_extralibs -lvfw32
 enabled decklink          && { require_headers DeckLinkAPI.h &&
                                { test_cpp_condition DeckLinkAPIVersion.h "BLACKMAGIC_DECKLINK_API_VERSION >= 0x0a090500" || die "ERROR: Decklink API version must be >= 10.9.5."; } }
 enabled libndi_newtek     && require_headers Processing.NDI.Lib.h