macOS Sierra 10.12.2
================================================================================
gnu gcc 6.3.0
isnan_macro_cmath.cpp:11:23: error: ‘isnan’ was not declared in this scope

clang 8.0.0
isnan_std_math.cpp:11:14: error: use of undeclared identifier 'std'



Linux - Scientific Linux release 7.3 (Nitrogen)
================================================================================
gcc 4.8.5
isnan_std_math.cpp:11:19: error: expected unqualified-id before ‘(’ token

gcc 4.9.4
isnan_std_math.cpp:11:19: error: expected unqualified-id before ‘(’ token

gcc 5.4.0
isnan_std_math.cpp:11:19: error: expected unqualified-id before ‘(’ token

gcc 6.2.0, 6.3.0, 7.1.0
no errors

icc 2016 (16.0.0)
isnan_std_cmath_math.cpp (11): error: expected an identifier
isnan_std_math.cpp       (11): error: expected an identifier
isnan_std_math_cmath.cpp (11): error: expected an identifier

icc 2017 (17.0.4)
no errors

icc 2018 (18.0.0)
no errors
