From 9eee8ec0bb5d1d2b23424d7264ff9becd8fa4813 Mon Sep 17 00:00:00 2001
From: Matthew Albrecht <mattparks5855@gmail.com>
Date: Fri, 20 Sep 2019 15:13:09 -0500
Subject: [PATCH] Check for existing uninstall target before creating.

---
 source/CMakeLists.txt | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index 5c924e844..31413acc3 100644
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -250,15 +250,17 @@ install(DIRECTORY ${XLNT_INCLUDE_DIR}/xlnt
 install(FILES ${XLNT_ROOT_DIR}/docs/xlnt.3
 DESTINATION ${MAN_DEST_DIR}/man3)
 
-# Configure uninstall
-configure_file("${XLNT_ROOT_DIR}/cmake/cmake_uninstall.cmake.in"
-  "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
-  IMMEDIATE @ONLY)
-
-# Add uninstall target
-add_custom_target(uninstall
-  COMMAND ${CMAKE_COMMAND} -P
-    ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake)
+if(NOT TARGET uninstall)
+  # Configure uninstall
+  configure_file("${XLNT_ROOT_DIR}/cmake/cmake_uninstall.cmake.in"
+    "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
+    IMMEDIATE @ONLY)
+
+  # Add uninstall target
+  add_custom_target(uninstall
+    COMMAND ${CMAKE_COMMAND} -P
+      ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake)
+endif()
 
 if(NOT MSVC)
   # Set pkg-config variables