create a way to pass in the c standard via tribits.

This file should be merged to Trilinos only after
pull request #239 in TriBITSPub has been propigated
to Trilinos. (TriBITSPub/TriBITS#239)
It merely sets the override for the sierra builds to
be the c11 posix standard.

cmake/ctest/drivers/parameterized/ctest_linux_nightly_generic_sierra.cmake

@@ -131,6 +131,8 @@ SET(EXTRA_CONFIGURE_OPTIONS
   "-DCMAKE_C_FLAGS:STRING=$ENV{JENKINS_C_FLAGS}"
   "-DCMAKE_Fortran_FLAGS=$ENV{JENKINS_Fortran_FLAGS}"
 
+  "-DTrilinos_C_Standard=c11"
+
 )
 
 IF (DEFINED ENV{JENKINS_BLAS_LIBRARY_DIRS})