Try to find settings.conf from SYSCONFDIR

Honor SYSCONFDIR as specified by CMake arguments instead of
using a hard-coded path.

Since GNUInstallDirs set CMAKE_INSTALL_FULL_SYSCONFDIR to
CMAKE_INSTALL_PREFIX/etc we need to change the default ourselves.

CMakeLists.txt

@@ -97,6 +97,13 @@ set( CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}" )
 set( CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}" )
 set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}" )
 
+# Better default installation paths: GNUInstallDirs defines
+# CMAKE_INSTALL_FULL_SYSCONFDIR to be CMAKE_INSTALL_PREFIX/etc by default
+# but we really want /etc
+if( NOT DEFINED CMAKE_INSTALL_SYSCONFDIR )
+    set( CMAKE_INSTALL_SYSCONFDIR "/etc" )
+endif()
+
 # make predefined install dirs available everywhere
 include( GNUInstallDirs )
 

src/calamares/CalamaresApplication.cpp

@@ -18,6 +18,7 @@
 #include <QDesktopWidget>
 #include "CalamaresApplication.h"
 
+#include "CalamaresConfig.h"
 #include "CalamaresWindow.h"
 #include "CalamaresVersion.h"
 #include "progresstree/ProgressTreeView.h"
@@ -156,7 +157,7 @@ CalamaresApplication::initSettings()
                 QDir::separator() +
                 "settings.conf" );
         }
-        settingsFileCandidatesByPriority.append( "/etc/calamares/settings.conf" );
+        settingsFileCandidatesByPriority.append( CMAKE_INSTALL_FULL_SYSCONFDIR "/calamares/settings.conf" );
         settingsFileCandidatesByPriority.append( CalamaresUtils::appDataDir()
                                                     .absoluteFilePath( "settings.conf" ) );
 

src/libcalamares/CalamaresConfig.h.in

@@ -6,6 +6,7 @@
 #define CMAKE_INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}"
 #define CMAKE_INSTALL_FULL_LIBDIR "${CMAKE_INSTALL_FULL_LIBDIR}"
 #define CMAKE_INSTALL_FULL_DATADIR "${CMAKE_INSTALL_FULL_DATADIR}/calamares"
+#define CMAKE_INSTALL_FULL_SYSCONFDIR "${CMAKE_INSTALL_FULL_SYSCONFDIR}"
 
 //cmakedefines for CMake variables (e.g. for optdepends) go here
 #cmakedefine WITH_PYTHON