message: Make math constants visible under msvc
diff: @@ -2,7 +2,7 @@ CMAKE_MINIMUM_REQUIRED(VERSION 3.2)
  PROJECT(SEGS)
  IF(MSVC)
  - add_definitions( -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_WARNINGS -DNOMINMAX)
  + add_definitions( -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_WARNINGS -DNOMINMAX -D_USE_MATH_DEFINES)
  ELSE()
  SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -std=c++11" )
  endif()
  