From the same file INSTALLyou are referring to ...
How to check the ABI of blas/lapack/atlas
One relatively simple and reliable way to check for the compiler used to build
a library is to use ldd on the library. If libg2c.so is a dependency, this
means that g77 has been used. If libgfortran.so is a a dependency, gfortran has
been used. If both are dependencies, this means both have been used, which is
almost always a very bad idea.
, gfortran , fortran-, , - g77, gfortran g77- , ... , : g77 ( ) , gfortran ( ) . , numpy ... ( numpy , , , ).