avformat/tls_schannel: add check for Windows 10 only types and defines

Old Mingw-w64 releases provided by some distros seemingly don't have them, so
check for them and disable the dtls protocol if unavailable.

Signed-off-by: James Almer <jamrial@gmail.com>

configure

@@ -2498,6 +2498,7 @@ TYPES_LIST="
     kCVImageBufferTransferFunction_ITU_R_2020
     kCVImageBufferTransferFunction_SMPTE_ST_428_1
     kVTQPModulationLevel_Default
+    SecPkgContext_KeyingMaterialInfo
     socklen_t
     struct_addrinfo
     struct_group_source_req
@@ -6822,6 +6823,7 @@ check_type "windows.h d3d12video.h" "ID3D12VideoEncoder"
 test_code cc "windows.h d3d12video.h" "D3D12_FEATURE_VIDEO feature = D3D12_FEATURE_VIDEO_ENCODER_CODEC" && \
 test_code cc "windows.h d3d12video.h" "D3D12_FEATURE_DATA_VIDEO_ENCODER_RESOURCE_REQUIREMENTS req" && enable d3d12_encoder_feature
 check_type "windows.h" "DPI_AWARENESS_CONTEXT" -D_WIN32_WINNT=0x0A00
+check_type "windows.h security.h schnlsp.h" SecPkgContext_KeyingMaterialInfo -DSECURITY_WIN32
 check_type "d3d9.h dxva2api.h" DXVA2_ConfigPictureDecode -D_WIN32_WINNT=0x0602
 check_func_headers mfapi.h MFCreateAlignedMemoryBuffer -lmfplat
 
@@ -7271,6 +7273,8 @@ enabled schannel &&
     schannel_extralibs="-lsecur32 -lncrypt -lcrypt32" ||
         disable schannel
 
+enabled schannel && check_cc dtls_protocol "windows.h security.h schnlsp.h" "int i = SP_PROT_DTLS1_X_CLIENT;" -DSECURITY_WIN32
+
 makeinfo --version > /dev/null 2>&1 && enable makeinfo  || disable makeinfo
 enabled makeinfo \
     && [ 0$(makeinfo --version | grep "texinfo" | sed 's/.*texinfo[^0-9]*\([0-9]*\)\..*/\1/') -ge 5 ] \