It is obnoxious that M(VA)PICH assumes that it is the only Fortran code I will ever build and asserts that I do not have the right to set the F90 environment variable in my shell, when this variable is not used at all by M(VA)PICH but might be used by other packages. I can understand prohibiting the use of --with-f90, but prohibiting "export F90" has far-reaching side-effects. I understand that configure is trying to help the user do the right thing (set FC and FCFLAGS), but this is the wrong way to do it. This is the code that I would like to see removed: # Since F90/F90FLAGS are replaced by FC/FCFLAGS, rather than silently # substituting them, i.e. FC=$F90 and FCFLAGS=$F90FLAGS, we choose to emit # an error message and abort to avoid any ambiguous/hidden bug in choosing # Fortran90 compilers. if test -n "$F90" -o -n "$F90FLAGS" ; then AC_MSG_ERROR([F90 and F90FLAGS are replaced by FC and FCFLAGS respectively in this configure, please unset F90/F90FLAGS and set FC/FCFLAGS instead and rerun configure again.]) fi Googling "F90FLAGS -mpich" reveals a litany of scientific applications that rely upon the F90 environment variable to be configured. Some users don't want to set F90 manually for every build if they know they always want to use F90=ifort, hence the shell export. Thanks, Jeff -- Jeff Hammond [email protected] http://jeffhammond.github.io/