From 7d45db99563c83a1a85722b1ee0f1fe10f8967d3 Mon Sep 17 00:00:00 2001
From: Daniel Pfeifer <daniel@pfeifer-mail.de>
Date: Mon, 10 Oct 2016 00:12:34 +0200
Subject: [PATCH] Don't require liblzma when using system libarchive

---
 CMakeLists.txt | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 92f641e9b9..827a19c53c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -383,19 +383,21 @@ macro (CMAKE_BUILD_UTILITIES)
 
   #---------------------------------------------------------------------
   # Build or use system liblzma for libarchive.
-  if(CMAKE_USE_SYSTEM_LIBLZMA)
-    find_package(LibLZMA)
-    if(NOT LIBLZMA_FOUND)
-      message(FATAL_ERROR "CMAKE_USE_SYSTEM_LIBLZMA is ON but LibLZMA is not found!")
+  if(NOT CMAKE_USE_SYSTEM_LIBARCHIVE)
+    if(CMAKE_USE_SYSTEM_LIBLZMA)
+      find_package(LibLZMA)
+      if(NOT LIBLZMA_FOUND)
+        message(FATAL_ERROR "CMAKE_USE_SYSTEM_LIBLZMA is ON but LibLZMA is not found!")
+      endif()
+      set(LZMA_INCLUDE_DIR ${LIBLZMA_INCLUDE_DIRS})
+      set(LZMA_LIBRARY ${LIBLZMA_LIBRARIES})
+    else()
+      add_subdirectory(Utilities/cmliblzma)
+      CMAKE_SET_TARGET_FOLDER(cmliblzma "Utilities/3rdParty")
+      set(LZMA_INCLUDE_DIR
+        "${CMAKE_CURRENT_SOURCE_DIR}/Utilities/cmliblzma/liblzma/api")
+      set(LZMA_LIBRARY cmliblzma)
     endif()
-    set(LZMA_INCLUDE_DIR ${LIBLZMA_INCLUDE_DIRS})
-    set(LZMA_LIBRARY ${LIBLZMA_LIBRARIES})
-  else()
-    add_subdirectory(Utilities/cmliblzma)
-    CMAKE_SET_TARGET_FOLDER(cmliblzma "Utilities/3rdParty")
-    set(LZMA_INCLUDE_DIR
-      "${CMAKE_CURRENT_SOURCE_DIR}/Utilities/cmliblzma/liblzma/api")
-    set(LZMA_LIBRARY cmliblzma)
   endif()
 
   #---------------------------------------------------------------------