cmake: globally enable POSITION_INDEPENDENT_CODE

Instead of setting the POSITION_INDEPENDENT_CODE flag on individual
targets, we simply enable it for everything in core/
Also, by utilizing PIE (Position Independent Executable) support in
CMake we make sure all our executables are build with PIE enabled if the
toolchain supports it.

core/CMakeLists.txt

@@ -1,6 +1,6 @@
 #   BAREOS® - Backup Archiving REcovery Open Sourced
 #
-#   Copyright (C) 2017-2022 Bareos GmbH & Co. KG
+#   Copyright (C) 2017-2023 Bareos GmbH & Co. KG
 #
 #   This program is Free Software; you can redistribute it and/or
 #   modify it under the terms of version three of the GNU Affero General Public
@@ -46,6 +46,11 @@ endif(CCACHE_FOUND)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
+# enable PIC/PIE by default
+include(CheckPIESupported)
+check_pie_supported()
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
 option(ENABLE_SANITIZERS "Build with ASan/LSan/UBSan enabled" OFF)
 if(ENABLE_SANITIZERS)
   if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")

core/src/droplet/libdroplet/CMakeLists.txt

@@ -1,6 +1,6 @@
 #   BAREOS® - Backup Archiving REcovery Open Sourced
 #
-#   Copyright (C) 2020-2022 Bareos GmbH & Co. KG
+#   Copyright (C) 2020-2023 Bareos GmbH & Co. KG
 #
 #   This program is Free Software; you can redistribute it and/or
 #   modify it under the terms of version three of the GNU Affero General Public
@@ -110,7 +110,6 @@ bareos_disable_warnings(
   C_ONLY
   ADD_FOR_LTO
 )
-set_property(TARGET droplet PROPERTY POSITION_INDEPENDENT_CODE ON)
 
 target_include_directories(
   droplet PUBLIC include ${LIBXML2_INCLUDE_DIR} ${JSONC_INCLUDE_DIRS}

core/src/lib/CMakeLists.txt

@@ -1,6 +1,6 @@
 #   BAREOS® - Backup Archiving REcovery Open Sourced
 #
-#   Copyright (C) 2017-2022 Bareos GmbH & Co. KG
+#   Copyright (C) 2017-2023 Bareos GmbH & Co. KG
 #
 #   This program is Free Software; you can redistribute it and/or
 #   modify it under the terms of version three of the GNU Affero General Public
@@ -151,7 +151,6 @@ target_compile_definitions(
           -DBAREOS_PROG_DATE_TIME="${BAREOS_PROG_DATE_TIME}"
           -DBAREOS_YEAR="${BAREOS_YEAR}"
 )
-set_target_properties(version-obj PROPERTIES POSITION_INDEPENDENT_CODE ON)
 
 target_link_libraries(
   bareos

core/src/stored/backends/CMakeLists.txt

@@ -29,7 +29,6 @@ macro(add_sd_backend backend_name)
     add_library(${backend_name} OBJECT)
     target_link_libraries(bareossd PRIVATE ${backend_name})
   endif()
-  set_property(TARGET ${backend_name} PROPERTY POSITION_INDEPENDENT_CODE ON)
 endmacro()
 
 if(${HAVE_GLUSTERFS})
@@ -70,9 +69,6 @@ endif()
 
 if(HAVE_DYNAMIC_SD_BACKENDS)
   add_library(bareossd-autochanger_test MODULE)
-  set_property(
-    TARGET bareossd-autochanger_test PROPERTY POSITION_INDEPENDENT_CODE ON
-  )
   target_sources(
     bareossd-autochanger_test PRIVATE autochanger_test_device.cc
                                       unix_file_device.cc