third-party: add xxHash config

Add CMake configuration for xxHash library

third-party/CMakeLists.txt

@@ -1,6 +1,6 @@
 #   BAREOS® - Backup Archiving REcovery Open Sourced
 #
-#   Copyright (C) 2022-2022 Bareos GmbH & Co. KG
+#   Copyright (C) 2022-2023 Bareos GmbH & Co. KG
 #
 #   This program is Free Software; you can redistribute it and/or
 #   modify it under the terms of version three of the GNU Affero General Public
@@ -21,3 +21,4 @@ message("Entering ${CMAKE_CURRENT_SOURCE_DIR}")
 
 add_subdirectory(CLI11 EXCLUDE_FROM_ALL)
 add_subdirectory(fmt EXCLUDE_FROM_ALL)
+include(./xxHash.cmake)

third-party/xxHash.cmake

@@ -0,0 +1,22 @@
+#   BAREOS® - Backup Archiving REcovery Open Sourced
+#
+#   Copyright (C) 2023-2023 Bareos GmbH & Co. KG
+#
+#   This program is Free Software; you can redistribute it and/or
+#   modify it under the terms of version three of the GNU Affero General Public
+#   License as published by the Free Software Foundation and included
+#   in the file LICENSE.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+#   Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program; if not, write to the Free Software
+#   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+#   02110-1301, USA.
+
+add_library(xxhash INTERFACE)
+target_include_directories(xxhash INTERFACE xxHash)
+add_library(xxHash::xxhash ALIAS xxhash)