Index: kdelibs4support-5.18.0/src/kdecore/kstandarddirs.cpp
===================================================================
--- kdelibs4support-5.18.0.orig/src/kdecore/kstandarddirs.cpp
+++ kdelibs4support-5.18.0/src/kdecore/kstandarddirs.cpp
@@ -292,7 +292,7 @@ static QString relativeInstallPath(const
             return QFile::decodeName(ICON_INSTALL_DIR "/");
         }
         if (strcmp("include", type) == 0) {
-            return QFile::decodeName(INCLUDE_INSTALL_DIR "/");
+            return QFile::decodeName(qgetenv("NIX_KDE_INCLUDE_DIR"));
         }
         break;
     case 'l':