From 0b50e60a67ef51b07edc6fc8d9e9be1075dda12f Mon Sep 17 00:00:00 2001
From: Paul Sonnenschein <paul@sonnenschein.ruhr>
Date: Tue, 23 Jul 2019 18:44:29 +0200
Subject: [PATCH] Fix compilation error on the Hurd.

* This commit disables the Linux backend on the Hurd because it fails to
  compile on Debian GNU/Hurd and does not seem to be useful on the Hurd
  (the code contains paths which do not exist on Hurd).
  .
  The build failure was caused by an unconditional use of PATH_MAX, which
  is not defined on the Hurd.
* Replace operating system check for the Hurd with an option.
* Do not use Polkit if not compiling the linux backlight backend.
---
 CMakeLists.txt    | 28 +++++++++++++++++++++++-----
 lxqtbacklight.cpp |  8 +++++++-
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6a26f19..537de65 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,6 +30,7 @@ set(LXQT_VERSION ${LXQT_MAJOR_VERSION}.${LXQT_MINOR_VERSION}.${LXQT_PATCH_VERSIO
 
 
 option(UPDATE_TRANSLATIONS "Update source translation translations/*.ts files" OFF)
+option(BUILD_BACKLIGHT_LINUX_BACKEND "Build the Linux backend for the backlight" ON)
 
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
@@ -41,7 +42,9 @@ find_package(lxqt-build-tools ${LXQTBT_MINIMUM_VERSION} REQUIRED)
 find_package(Qt5 ${QT_MINIMUM_VERSION} CONFIG REQUIRED Widgets DBus LinguistTools)
 find_package(Qt5Xdg ${QTXDG_MINIMUM_VERSION} REQUIRED)
 find_package(KF5WindowSystem ${KF5_MINIMUM_VERSION} REQUIRED)
-find_package(PolkitQt5-1 REQUIRED)
+if (BUILD_BACKLIGHT_LINUX_BACKEND)
+    find_package(PolkitQt5-1 REQUIRED)
+endif (BUILD_BACKLIGHT_LINUX_BACKEND)
 if (NOT APPLE)
     find_package(Qt5 ${QT_MINIMUM_VERSION} CONFIG REQUIRED X11Extras)
     find_package(X11 REQUIRED)
@@ -51,7 +54,10 @@ message(STATUS "Building ${PROJECT_NAME} with Qt ${Qt5Core_VERSION}")
 include(CMakePackageConfigHelpers)
 include(GNUInstallDirs) # Standard directories for installation
 
-add_subdirectory(lxqtbacklight/linux_backend/driver)
+if (BUILD_BACKLIGHT_LINUX_BACKEND)
+    add_subdirectory(lxqtbacklight/linux_backend/driver)
+    add_definitions(-DUSE_BACKLIGHT_LINUX_BACKEND)
+endif (BUILD_BACKLIGHT_LINUX_BACKEND)
 
 set(LXQT_PKG_CONFIG_DESCRIPTION "Shared library for LXQt applications")
 
@@ -136,7 +142,6 @@ set(SRCS
     lxqtrotatedwidget.cpp
     lxqtbacklight.cpp
     lxqtbacklight/virtual_backend.cpp
-    lxqtbacklight/linux_backend/linuxbackend.cpp
 )
 
 if (NOT APPLE)
@@ -145,6 +150,12 @@ if (NOT APPLE)
     )
 endif (NOT APPLE)
 
+if (BUILD_BACKLIGHT_LINUX_BACKEND)
+    list (APPEND SRCS
+        lxqtbacklight/linux_backend/linuxbackend.cpp
+    )
+endif (BUILD_BACKLIGHT_LINUX_BACKEND)
+
 set(MOCS
     lxqthtmldelegate.h
     lxqtpowermanager.h
@@ -163,7 +174,6 @@ set(MOCS
     lxqtgridlayout.h
     lxqtrotatedwidget.h
     lxqtbacklight/virtual_backend.h
-    lxqtbacklight/linux_backend/linuxbackend.h
 )
 
 if (NOT APPLE)
@@ -172,6 +182,12 @@ if (NOT APPLE)
     )
 endif (NOT APPLE)
 
+if (BUILD_BACKLIGHT_LINUX_BACKEND)
+    list (APPEND SRCS
+        lxqtbacklight/linux_backend/linuxbackend.h
+    )
+endif (BUILD_BACKLIGHT_LINUX_BACKEND)
+
 set(FORMS
     configdialog/lxqtconfigdialog.ui
 )
@@ -395,7 +411,9 @@ install(FILES ${LXQT_CONFIG_FILES}
     COMPONENT Runtime
 )
 
-install(FILES ${POLKIT_FILES} DESTINATION "${POLKITQT-1_POLICY_FILES_INSTALL_DIR}")
+if (BUILD_BACKLIGHT_LINUX_BACKEND)
+    install(FILES ${POLKIT_FILES} DESTINATION "${POLKITQT-1_POLICY_FILES_INSTALL_DIR}")
+endif (BUILD_BACKLIGHT_LINUX_BACKEND)
 
 #************************************************
 # Create and install pkgconfig file
diff --git a/lxqtbacklight.cpp b/lxqtbacklight.cpp
index 581eb9d..c31f219 100644
--- a/lxqtbacklight.cpp
+++ b/lxqtbacklight.cpp
@@ -18,13 +18,19 @@
 
 #include "lxqtbacklight.h"
 #include "lxqtbacklight/virtual_backend.h"
-#include "lxqtbacklight/linux_backend/linuxbackend.h"
+#ifdef USE_BACKLIGHT_LINUX_BACKEND
+    #include "lxqtbacklight/linux_backend/linuxbackend.h"
+#endif
 
 namespace LXQt {
 
 Backlight::Backlight(QObject *parent):QObject(parent)
 {
+#ifdef USE_BACKLIGHT_LINUX_BACKEND
     m_backend = (VirtualBackEnd *) new LinuxBackend(this);
+#else
+    m_backend = new VirtualBackEnd(this);
+#endif
     connect(m_backend, &VirtualBackEnd::backlightChanged, this, &Backlight::backlightChangedSlot);
 }