#1217 CMake: minor improvements; in peculiar the trick found on the Web...

#1217 CMake: minor improvements; in peculiar the trick found on the Web concerning default CMAKE_BUILD_TYPE didn't work correctly; replaced it by another one which seems to fare better.

CMakeLists.txt

 # A minimum version for cmake command is required.
 cmake_minimum_required(VERSION 3.8)
 
-# TODO Add check whether the provided value is valid.
 
 
 # ===================================================================================================================
 # Include a file with default setting. Some of them might be overriden by command line, such as the C or C++ compiler.
 # ===================================================================================================================
 if(NOT SETTINGS_FILE)
-    message(FATAL_ERROR "-DSETTINGS_FILE must be present in the command line and point to a file that specify the paths and settings to use in the build. A default one is defined in cmake/Paths.cmake; feel free to copy and adapt it to your needs.")
+    message(FATAL_ERROR "-DSETTINGS_FILE must be present in the command line and point to a file that specify the paths and settings to use in the build. Examples are given in cmake/Settings folder; feel free to copy and adapt them to your needs.")
 endif()
 
 include(${SETTINGS_FILE})
@@ -35,20 +34,18 @@ endif()
 # WARNING: all those calls must occur BEFORE the call to project, so that overriding remains possible.
 # ===================================================================================================================
 
-# From https://cmake.org/pipermail/cmake/2008-September/023808.html
-# Ensure if the user doesn't specify arenything in command line debug is chosen (CMake default is no optimization and no debug symbol, which is rather useless).
-if(DEFINED CMAKE_BUILD_TYPE)
-   set(CMAKE_BUILD_TYPE ${CMAKE_BUILD_TYPE} CACHE STRING "Choose the type of
-build, options are: None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used) Debug
-Release RelWithDebInfo MinSizeRel.")
-else()
-   set(CMAKE_BUILD_TYPE Debug CACHE STRING "Choose the type of build,
-options are: None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used) Debug Release
-RelWithDebInfo MinSizeRel.")
+# From http://cmake.3232098.n2.nabble.com/Default-value-for-CMAKE-BUILD-TYPE-td7550756.html#a7550797
+# Set a default build type if none was specified
+if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+  message(STATUS "Setting build type to 'Debug' as none was specified.")
+  set(CMAKE_BUILD_TYPE Debug CACHE STRING "Choose the type of build." FORCE)
+  # Set the possible values of build type for cmake-gui
+  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release"
+    "MinSizeRel" "RelWithDebInfo")
 endif()
 
 set(MOREFEM_INSTALL_DIR ${MOREFEM_INSTALL_DIR}/${CMAKE_BUILD_TYPE})
-
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_LIST_DIR}/cmake)
 # Set C and CXX compilers from the values read in the setting file. Might be overridden in command line.
 
 if (NOT DEFINED CMAKE_C_COMPILER)
@@ -69,9 +66,9 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
-set(CMAKE_CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_EXTENSIONS OFF) # I want c++17, not gnu++17.
 
-include(cmake/CustomCommands.cmake)
+include(CustomCommands)
 
 # All --all_load in target_link_libraries of executables if STATIC library are chose.
     
@@ -83,7 +80,7 @@ endif()
 
 MESSAGE("Generated with config types: ${CMAKE_CONFIGURATION_TYPES}")
 
-include(cmake/Compiler.cmake)
+include(Compiler)
 
 # Add LTO support in non debug mode.
 if (${CMAKE_BUILD_TYPE} STREQUAL "Debug")

cmake/Compiler.cmake

@@ -15,6 +15,8 @@ if(${CMAKE_C_COMPILER_ID} STREQUAL "AppleClang" OR ${CMAKE_C_COMPILER_ID} STREQU
 
     add_cxx_compiler_flag("-stdlib=libc++") 
     
+    message("BUILD TYPE" ${CMAKE_BUILD_TYPE})
+    
     if (${CMAKE_BUILD_TYPE} STREQUAL "Debug")
         add_definitions(-D_LIBCPP_DEBUG2=0) # Additional checks such as index out of bounds in vectors in libc++; might 
                                             # be removed at any point from libc++.