Fix fseek test

[islas]

TYPE: bug fix

KEYWORDS: fseek, compilation, cmake

SOURCE: internal

DESCRIPTION OF CHANGES: Problem: The fseek test lacks correct syntax causing false negative reports of feature not existing when newer compiler standards disallow this.

Solution: Add void to the main program in the fseek test. Also to add further robustness in detecting this feature, use the -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE=1 generally *nix standard defines.

LIST OF MODIFIED FILES: M CMakeLists.txt M confcheck/CMakeLists.txt M tools/fseek_test.c

RELEASE NOTE: Fix fseek test