From 48db48207f16008bc9ae265ee0c7ee71c826fba1 Mon Sep 17 00:00:00 2001
From: Olivier Le Doeuff <olivier.ldff@gmail.com>
Date: Wed, 19 Oct 2022 16:26:58 +0200
Subject: [PATCH] Allow to install a target without `INCLUDE_DESTINATION` (#33)

* Allow to install a target without `INCLUDE_DESTINATION`

Concrete use case:
A library like `gtest_main` that define a `main` symbols just need to be linked to.

* All `INCLUDE_DIR` to be empty too
---
 CMakeLists.txt | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f2e27d1..868d490 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -165,13 +165,15 @@ function(packageProject)
     set(PROJECT_INCLUDE_HEADER_PATTERN "*")
   endif()
 
-  install(
-    DIRECTORY ${PROJECT_INCLUDE_DIR}/
-    DESTINATION ${PROJECT_INCLUDE_DESTINATION}
-    COMPONENT "${PROJECT_NAME}_Development"
-    FILES_MATCHING
-    PATTERN "${PROJECT_INCLUDE_HEADER_PATTERN}"
-  )
+  if(PROJECT_INCLUDE_DESTINATION AND PROJECT_INCLUDE_DIR)
+    install(
+      DIRECTORY ${PROJECT_INCLUDE_DIR}/
+      DESTINATION ${PROJECT_INCLUDE_DESTINATION}
+      COMPONENT "${PROJECT_NAME}_Development"
+      FILES_MATCHING
+      PATTERN "${PROJECT_INCLUDE_HEADER_PATTERN}"
+    )
+  endif()
 
   set(${PROJECT_NAME}_VERSION
       ${PROJECT_VERSION}