CMake: Use interface library for better FindLibLZMA compatibility.

https://www.mail-archive.com/xz-devel@tukaani.org/msg00446.html

Thanks to Markus Rickert.

CMakeLists.txt

@@ -454,9 +454,16 @@ file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/liblzma-config.cmake"
 "include(CMakeFindDependencyMacro)
 set(THREADS_PREFER_PTHREAD_FLAG TRUE)
 find_dependency(Threads)
+
 include(\"\${CMAKE_CURRENT_LIST_DIR}/liblzma-targets.cmake\")
-# Be compatible with the spelling used by the FindLibLZMA module:
-add_library(LibLZMA::LibLZMA ALIAS liblzma::liblzma)
+
+# Be compatible with the spelling used by the FindLibLZMA module. This
+# doesn't use ALIAS because it would make CMake resolve LibLZMA::LibLZMA
+# to liblzma::liblzma instead of keeping the original spelling. Keeping
+# the original spelling is important for good FindLibLZMA compatibility.
+add_library(LibLZMA::LibLZMA INTERFACE IMPORTED)
+set_target_properties(LibLZMA::LibLZMA PROPERTIES
+                      INTERFACE_LINK_LIBRARIES liblzma::liblzma)
 ")
 
 # Set CMAKE_INSTALL_LIBDIR and friends.