Fix #403, patches for older system compatibility

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[x] I reviewed the Contributing Guide.
[x] I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution Do not assume INTMAX_MAX or UINT64_C macros are available. Notably, these are absent on VxWorks 6.9,

Fixes #403

Testing performed Build on VxWorks 6.9

Expected behavior changes Compile succeeds. Test cases that depend on host system 64-bit macros will not be run

System(s) tested on VxWorks 6.9

Contributor Info - All information REQUIRED for consideration of pull request Joseph Hickey, Vantage Systems, Inc.

nasa / CF