Add cmake cache var to allow for use of system sqlite

Signed-off-by: Nicholas Frizzell <nfrizzel@redhat.com>

package-system/sqlite/FindSQLite.cmake

@@ -6,26 +6,38 @@
 #
 #
 
-# this file actually ingests the library and defines targets.
-set(TARGET_WITH_NAMESPACE "3rdParty::SQLite")
+set(MY_NAME "SQLite")
+set(TARGET_WITH_NAMESPACE "3rdParty::${MY_NAME}")
 if (TARGET ${TARGET_WITH_NAMESPACE})
     return()
 endif()
 
-set(MY_NAME "SQLite")
-
-
-set(${MY_NAME}_INCLUDE_DIR ${CMAKE_CURRENT_LIST_DIR}/SQLite)
-set(${MY_NAME}_LIBS_DIR ${CMAKE_CURRENT_LIST_DIR}/SQLite/lib)
-set(${MY_NAME}_LIBRARY ${${MY_NAME}_LIBS_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}sqlite3${CMAKE_STATIC_LIBRARY_SUFFIX})
-
-add_library(${TARGET_WITH_NAMESPACE} STATIC IMPORTED GLOBAL)
+if (LY_SYSTEM_PACKAGE_${MY_NAME})
+
+    find_package(SQLite3)
+    if (NOT SQLite3_FOUND)
+        message(FATAL_ERROR "LY_SYSTEM_PACKAGE_${MY_NAME} specified but development files for ${MY_NAME} not found.")
+    else()
+        set_target_properties(SQLite::SQLite3 PROPERTIES LY_SYSTEM_LIBRARY TRUE)
+        add_library(${TARGET_WITH_NAMESPACE} ALIAS SQLite::SQLite3)
+        set(${MY_NAME}_FOUND True)
+    endif()
+
+else()
+
+    set(${MY_NAME}_INCLUDE_DIR ${CMAKE_CURRENT_LIST_DIR}/SQLite)
+    set(${MY_NAME}_LIBS_DIR ${CMAKE_CURRENT_LIST_DIR}/SQLite/lib)
+    set(${MY_NAME}_LIBRARY ${${MY_NAME}_LIBS_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}sqlite3${CMAKE_STATIC_LIBRARY_SUFFIX})
+
+    add_library(${TARGET_WITH_NAMESPACE} STATIC IMPORTED GLOBAL)
+
+    set_target_properties(${TARGET_WITH_NAMESPACE} PROPERTIES IMPORTED_LOCATION "${${MY_NAME}_LIBRARY}")
+
+    ly_target_include_system_directories(TARGET ${TARGET_WITH_NAMESPACE} INTERFACE ${${MY_NAME}_INCLUDE_DIR})
+
+    target_link_libraries(${TARGET_WITH_NAMESPACE} 
+                          INTERFACE ${CMAKE_DL_LIBS})
+
+    set(${MY_NAME}_FOUND True)
 
-set_target_properties(${TARGET_WITH_NAMESPACE} PROPERTIES IMPORTED_LOCATION "${${MY_NAME}_LIBRARY}")
-
-ly_target_include_system_directories(TARGET ${TARGET_WITH_NAMESPACE} INTERFACE ${${MY_NAME}_INCLUDE_DIR})
-
-target_link_libraries(${TARGET_WITH_NAMESPACE} 
-                      INTERFACE ${CMAKE_DL_LIBS})
-
-set(${MY_NAME}_FOUND True)
+endif()