Fix HighDPI support, remove cxxbasics, improve LTO + PIE detection

.travis.yml

@@ -1,13 +1,13 @@
 language: cpp
 compiler: clang
 sudo: require
-dist: trusty
+dist: xenial
 before_install:
-- sudo add-apt-repository ppa:beineri/opt-qt591-trusty -y
+- sudo add-apt-repository ppa:beineri/opt-qt-5.15.0-xenial -y
 - sudo apt-get update -qq
 install:
 - sudo apt-get -y -qq install cmake
-- sudo apt-get -y -qq install libgl1-mesa-dev qt59base qt59imageformats qt59svg qt59charts-no-lgpl qt59tools
+- sudo apt-get -y -qq install libgl1-mesa-dev qt515base qt515imageformats qt515svg qt515charts-no-lgpl qt515tools
 - source /opt/qt*/bin/qt*-env.sh
 before_script:
 - mkdir build && cd build

CMakeLists.txt

@@ -1,8 +1,36 @@
 cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
 project(Stacer)
 
-# Adding features(build cache + faster linkers) and reasonable defaults(Debug build by default)
-include("${CMAKE_CURRENT_SOURCE_DIR}/cmake/cxxbasics/CXXBasics.cmake")
+# Build with PIC and PIE(default: ON)
+option(CMAKE_POSITION_INDEPENDENT_CODE "Determines whether position independent executables or shared libraries will be created" ON)
+
+# Build with LTO(default: OFF)
+option(CMAKE_INTERPROCEDURAL_OPTIMIZATION "If set to true, enables interprocedural optimizations if they are known to be supported by the compiler" OFF)
+
+if("${CMAKE_BUILD_TYPE}" STREQUAL "Release" OR "${CMAKE_BUILD_TYPE}" STREQUAL "MinSizeRel")
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION ON)
+endif()
+
+# Apply PIE flags if cmake_minimum_required is over 3.14(see policy CMP0083)
+if(POLICY CMP0083)
+    cmake_policy(SET CMP0083 NEW)
+    include(CheckPIESupported)
+    check_pie_supported()
+    set(CMAKE_POLICY_DEFAULT_CMP0083 NEW)
+endif(POLICY CMP0083)
+
+# Build with LTO, if explicitly enabled
+if(CMAKE_INTERPROCEDURAL_OPTIMIZATION)
+    if(POLICY CMP0069)
+        cmake_policy(SET CMP0069 NEW)
+        include(CheckIPOSupported)
+        check_ipo_supported()
+
+        set(CMAKE_POLICY_DEFAULT_CMP0069 NEW)
+        set(CMAKE_EXE_LINKER_FLAGS    "${CMAKE_EXE_LINKER_FLAGS} ${CMAKE_CXX_FLAGS}")
+        set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${CMAKE_CXX_FLAGS}")
+    endif(POLICY CMP0069)
+endif(CMAKE_INTERPROCEDURAL_OPTIMIZATION)
 
 # Setting a cleaner directory structure for the generated binaries
 set(CMAKE_BINARY_DIR        "${CMAKE_BINARY_DIR}/output")