Boost why U keep failing.

Former-commit-id: dd1bf2583ac9893a31eed0c6c8c6abec63419a51

shared/cmake/libigl.cmake

@@ -135,6 +135,10 @@ endif()
 if(LIBIGL_WITH_CGAL)
   # CGAL Core is needed for
   # `Exact_predicates_exact_constructions_kernel_with_sqrt`
+  set(BOOST_ROOT "${LIBIGL_EXTERNAL}/boost")
+  set(BOOST_LIBRARYDIR "${LIBIGL_EXTERNAL}/boost/lib")
+  set(BOOST_INCLUDEDIR "${LIBIGL_EXTERNAL}/boost/include/boost-1_66")
+  set(Boost_DEBUG ON CACHE BOOL "" FORCE)
   find_package(CGAL COMPONENTS Core)
   if(CGAL_FOUND)
     compile_igl_module("cgal" "copyleft/")
@@ -142,11 +146,9 @@ if(LIBIGL_WITH_CGAL)
       set(Boost_USE_STATIC_LIBS ON) # Favor static Boost libs on Windows
       target_include_directories(igl_cgal ${IGL_SCOPE} "${GMP_INCLUDE_DIR}" "${MPFR_INCLUDE_DIR}")
     endif()
-    set(BOOST_ROOT "${LIBIGL_EXTERNAL}/boost")
-    set(BOOST_LIBRARYDIR "${LIBIGL_EXTERNAL}/boost/lib")
-    set(BOOST_INCLUDEDIR "${LIBIGL_EXTERNAL}/boost/include")
-    set(Boost_NO_BOOST_CMAKE OFF CACHE BOOL "" FORCE)
     find_package(Boost 1.48 REQUIRED thread system)
+    message("Boost include: " ${Boost_INCLUDE_DIRS})
+    message("Boost include: " ${Boost_LIBRARIES})
     target_include_directories(igl_cgal ${IGL_SCOPE} ${CGAL_INCLUDE_DIRS} ${Boost_INCLUDE_DIRS})
     target_link_libraries(igl_cgal ${IGL_SCOPE} CGAL::CGAL CGAL::CGAL_Core ${Boost_LIBRARIES})
   else()