This blog is updated daily.
A general description is here.
The list of compilers searched for ‘F95’ has been modernized, and that
chosen for ‘FC’ will be used as the default. in particular, ‘gfortran’
is now the first choice, not ‘f95’: set ‘FC’ in ‘config.site’ to
override this if necessary.
Macros ‘FFLAGS’ and ‘FCFLAGS’ remain distinct to allow for a compiler which needs a flag to select free- or fixed-form Fortran (most use the source-file extension to choose: ‘.f’ is fixed-form and ‘.f90’ and ‘.f95’ are free-form).
If only one of them is set, its value is used for both.
The special-casing of ‘CFLAGS’, ‘CXXFLAGS’ and ‘FFLAGS’ for Intel compilers on Linux has been removed: we do not have recent experience but the generic defaults now chosen are the same as those previously special-cased for ‘x86_64’ on Intel.
If necessary, override the defaults on the ‘configure’ command line or in file ‘config.site’.
Macro ‘FCLIBS’, which has sometimes been needed on Solaris, has been renamed to ‘FCLIBS_XTRA’.
Macro ‘F77’ is always set to the value of ‘FC’, so the latter should be set to user-select the Fortran compiler for both fixed-form and free-form Fortran. In particular, ‘gfortran’ is now the first choice for ‘F77’, not ‘f95’.
Make macros ‘F77’, ‘FCPIFCPLAGS’ and ‘SHLIB_OPENMP_FCFLAGS’ are deprecated in favour of ‘FC’, ‘FPICFLAGS’ and ‘SHLIB_OPENMP_FFLAGS’ respectively.
The default method of ‘seq()’ now avoids integer overflow, thanks to the report and "cumsum" patch of Suharto Anggono's PR#17497.