Improved the help messages cmake outputs to tell the user how to install

optional dependencies such as X11, BLAS, and LAPACK.

dlib/CMakeLists.txt

@@ -111,10 +111,10 @@ if (NOT TARGET dlib)
                include_directories(${x11_path})
                set(dlib_needed_libraries ${dlib_needed_libraries} ${xlib} )
             else()
-               message(" ***********************************************************************************")
-               message(" ****** DLIB GUI SUPPORT DISABLED BECAUSE X11 DEVELOPMENT LIBRARIES NOT FOUND ******")
-               message(" ****** Make sure libx11-dev is installed if you want GUI support             ******")
-               message(" ***********************************************************************************")
+               message(" *****************************************************************************")
+               message(" *** DLIB GUI SUPPORT DISABLED BECAUSE X11 DEVELOPMENT LIBRARIES NOT FOUND ***")
+               message(" *** Make sure libx11-dev is installed if you want GUI support             ***")
+               message(" *****************************************************************************")
                set(DLIB_NO_GUI_SUPPORT ON CACHE STRING ${DLIB_NO_GUI_SUPPORT_STR} FORCE )
             endif()
          endif()
@@ -142,10 +142,10 @@ if (NOT TARGET dlib)
                include_directories(${X11_INCLUDE_DIR})
                set (dlib_needed_libraries ${dlib_needed_libraries} ${X11_LIBRARIES})
             else()
-               message(" ***********************************************************************************")
-               message(" ****** DLIB GUI SUPPORT DISABLED BECAUSE X11 DEVELOPMENT LIBRARIES NOT FOUND ******")
-               message(" ****** Make sure libx11-dev is installed if you want GUI support             ******")
-               message(" ***********************************************************************************")
+               message(" *****************************************************************************")
+               message(" *** DLIB GUI SUPPORT DISABLED BECAUSE X11 DEVELOPMENT LIBRARIES NOT FOUND ***")
+               message(" *** Make sure libx11-dev is installed if you want GUI support             ***")
+               message(" *****************************************************************************")
                set(DLIB_NO_GUI_SUPPORT ON CACHE STRING ${DLIB_NO_GUI_SUPPORT_STR} FORCE )
             endif()
          endif()

dlib/cmake_find_blas.txt

@@ -163,7 +163,12 @@ if (UNIX)
 
 
    if (NOT blas_found)
-      message(STATUS "***** No BLAS library found *****")
+      message(" *****************************************************************************")
+      message(" *** No BLAS library found so using dlib's built in BLAS.  However, if you ***")
+      message(" *** install an optimized BLAS such as openblas or the Intel MKL your code ***")
+      message(" *** will run faster.  On Ubuntu you can install openblas by executing:    ***")
+      message(" ***    sudo apt-get install libopenblas-dev liblapack-dev                 ***")
+      message(" *****************************************************************************")
    endif()
 
 endif()