It fails to compile because DP is used but not declared, and is not
exported via module LAPACK.

NAG Fortran Compiler Release 5.2(668)
Warning: ex_08.4.3.f90: File ex_08.4.1.f90 containing module LAPACK needs recompilation
Error: ex_08.4.3.f90, line 4: Implicit type for DP
       detected at DP@)
Error: ex_08.4.3.f90, line 4: DP is not a constant
       detected at _@DP
Warning: ex_08.4.3.f90, line 20: Symbol DP referenced but never set
         detected at MAIN@<end-of-statement>
[NAG Fortran Compiler pass 1 error termination, 2 errors, 2 warnings]