[CMake] Intel C99 standard

[Daniel Wirtz]

Folks,

so CMake introduced those nice features "[CMAKE_]C_STANDARD[_REQUIRED]" 
etc to automatically
add appropriate flags to compilers. so, while i can see there's settings 
for clang and gnu in Modules/Compiler/..
the Intel-* script do not define any (current cmake 3.3.1).
but the intel devzone says there are flags you can use: 
https://software.intel.com/en-us/articles/c99-support-in-intel-c-compiler

i ran into that problem as the "SUPERLU_DIST" package requires C99 
standard, which failed to compile using intel compilers
because cmake did not add the "-std=c99" c flags.
so has that simply not come up yet or is there a reason cmake does not 
add those flags for intel?

thanks!

-- 
Dr. Daniel Wirtz
Dipl. Math. Dipl. Inf.
SRC SimTech
Pfaffenwaldring 5a
+49 711 685 60044