title: Make double-precision default in g77, Fortran compiler
body: <p>Is there an analog of the "-fdefault-real-8" gfortran (the GNU Fortran 95 compiler) option in g77 (the GNU Fortran 77 compiler)?  This option sets the default real type to an 8-byte wide type.</p>
  
  <p>I currently have code where single-precision arithmetic is limiting my accuracy, and so I need double-precision.  (It's not just intermediate values that I want to be in double-precision, which is an FPU flag; I want everything to be in double-precision.)  I know that I have some other approaches (using gfortran, using other compilers, or changing all REALs to DOUBLE PRECISIONs), but they're not ideal for my situation.</p>
  
  <p>So, is there any way to set the default real type to be double precision, namely 8 bytes wide, in g77?</p>