__ILP32_OFFBIG_CFLAGS

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
extern (C)
static if(!is(typeof(__ILP32_OFFBIG_CFLAGS)))
enum __ILP32_OFFBIG_CFLAGS = "-m32 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64";

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