Use location of XKBcommon headers, don't expect build in source directory

CMakeLists.txt

@@ -47,6 +47,7 @@ include_directories(
    ${WLC_INCLUDE_DIRS}
    ${PCRE_INCLUDE_DIRS}
    ${JSONC_INCLUDE_DIRS}
+   ${XKBCOMMON_INCLUDE_DIRS}
    include/
 )
 
@@ -88,12 +89,12 @@ ADD_CUSTOM_TARGET(man ALL
   DEPENDS ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/sway.5)
 
 INSTALL(
-  FILES ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/sway.1
+  FILES ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/sway.1
   DESTINATION ${CMAKE_INSTALL_PREFIX}/share/man/man1
 )
 
 INSTALL(
-  FILES ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/sway.5
+  FILES ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/sway.5
   DESTINATION ${CMAKE_INSTALL_PREFIX}/share/man/man5
 )