add X11 link library

Author: mbaetgen-wup

tests/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory(libprojectM)
 add_subdirectory(playlist)
+add_subdirectory(cxx-interface)

tests/cxx-interface/CMakeLists.txt

@@ -12,11 +12,21 @@ project(projectM_CXX_Test
 
 find_package(projectM4 REQUIRED)
 
+if(UNIX AND NOT APPLE)
+    find_package(X11 REQUIRED)
+endif()
+
 add_executable(projectM4_CXX_Test
         main.cpp
         )
 
-target_link_libraries(projectM4_CXX_Test
-        libprojectM::projectM
-        glad
-        )
+if(UNIX AND NOT APPLE)
+    target_link_libraries(projectM4_CXX_Test
+            libprojectM::projectM
+            X11::X11
+    )
+else()
+    target_link_libraries(projectM4_CXX_Test
+            libprojectM::projectM
+    )
+endif()