refactor: use Release build type by default

CMakeLists.txt

@@ -12,6 +12,16 @@ endif(POLICY CMP0086)
 # Add etc/cmake to CMake's search path so we can put our private stuff there
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/etc/cmake)
 
+# Set a default build type if none was specified
+# This must precede the project() line, which would set the CMAKE_BUILD_TYPE
+# to 'Debug' with single-config generators on Windows.
+# Note that we must do this only if PROJECT_NAME is not set at this point. If
+# it is set, it means that plfit is being used as a subproject of another
+# project.
+if(NOT PROJECT_NAME)
+  include(BuildType)
+endif()
+
 project(
   plfit
   VERSION 0.9.6

etc/cmake/BuildType.cmake

@@ -0,0 +1,12 @@
+# Taken from https://blog.kitware.com/cmake-and-the-default-build-type/
+
+# Set the default build type to "Release"
+set(default_build_type "Release")
+
+get_property(isMultiConfig GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+if(NOT isMultiConfig AND NOT CMAKE_BUILD_TYPE)
+  message(STATUS "Setting build type to '${default_build_type}' as none was specified.")
+  set(CMAKE_BUILD_TYPE "${default_build_type}" 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()