... and those people who are executing the binary out of the build directory are probably running the regression test (i.e., "make; make check") and on most developer machines, if they're lucky they have enough memory that the executable will still be in their page cache. :-)
This being said, on modern file systems (i.e., btrfs, ext4, xfs, et. al), delayed allocation should mostly hide this problem; and if not, and the linker can estimate in advance how big the resulting binary will be, it could be modified to use the fallocate(2) system call.
-- Ted
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