mesa-users] Installation Problem: "Function 'isnan' at (1) has no IMPLICIT type"

[Ricky Olivier]

Hi,

I got the following problem when trying to install MESA:

/home/ricky/mesa_1.1.1/utils
building utils package.

gfortran  -fopenmp -I../public -I../../include -Wunused-value 
-Wuninitialized -Werror -W -fimplicit-none   -O2 -c -ffree-form 
../private/utils_isnan_okay.f
../private/utils_isnan_okay.f:38.29:

         check_for_bad_num = isnan(x) .or. is_inf(x)
                            1
Error: Function 'isnan' at (1) has no IMPLICIT type
make: *** [utils_isnan_okay.o] Error 1

/home/ricky/mesa_1.1.1/utils/make
FAILED

Could anyone please advise as to what the problem is maybe? I installed 
ndiff-2.00 and the latest version of MESA on sourceforge.net (as of 
today 10 Dec. 2009).

Regards,
Enrico