contrib: enable support for custom SDKROOTs without messing with the system...

contrib: enable support for custom SDKROOTs without messing with the system and add support for tvOS

contrib/bootstrap

@@ -158,6 +158,10 @@ add_make_enabled()
 
 check_ios_sdk()
 {
+    if test "$VLCSDKROOT"
+    then
+	    SDKROOT="$VLCSDKROOT"
+    else
 		if test -z "$SDKROOT"
 		then
 		   SDKROOT=`xcode-select -print-path`/Platforms/iPhone${PLATFORM}.platform/Developer/SDKs/iPhone${PLATFORM}${SDK_VERSION}.sdk
@@ -165,6 +169,7 @@ check_ios_sdk()
 		else
 		   SDKROOT="$SDKROOT"
 		fi
+    fi
 
     if [ ! -d "${SDKROOT}" ]
     then
@@ -263,6 +268,10 @@ case "${OS}" in
 				;;
 			esac;
 		fi
+		if test "$BUILDFORTVOS"
+		then
+			add_make_enabled "HAVE_TVOS"
+		fi
 		;;
 	*bsd*)
 		add_make_enabled "HAVE_BSD"

contrib/src/vpx/rules.mak

@@ -91,7 +91,11 @@ VPX_CONF += --sdk-path=$(MACOSX_SDK)
 endif
 ifdef HAVE_IOS
 VPX_CONF += --sdk-path=$(IOS_SDK) --enable-vp8-decoder --disable-vp8-encoder --disable-vp9-encoder
+ifdef HAVE_TVOS
+VPX_LDFLAGS := -L$(IOS_SDK)/usr/lib -isysroot $(IOS_SDK) -mtvos-version-min=9.0
+else
 VPX_LDFLAGS := -L$(IOS_SDK)/usr/lib -isysroot $(IOS_SDK) -miphoneos-version-min=6.1
+endif
 ifeq ($(ARCH),aarch64)
 VPX_LDFLAGS += -arch arm64
 else