Telegram: fix path for clang

net-im/telegram-desktop/telegram_desktop-4.11.3.recipe

@@ -137,8 +137,8 @@ BUILD()
 		sed -i -e '/-fstack-protector-all/d' cmake/options_linux.cmake
 		sed -i -e '/_GLIBCXX_ASSERTIONS/d' cmake/options_linux.cmake
 		# use clang for build
-		export CC="/bin/clang"
-		export CXX="/bin/clang++"
+		export CC="clang"
+		export CXX="clang++"
 	fi
 
 	# get API_ID and API_HASH from Debian