/usr/include/astrometry/os-features-config.h is in libastrometry-dev 0.67+dfsg-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | #define NEED_CANONICALIZE_FILE_NAME 0
#define NEED_DECLARE_QSORT_R 0
#define NEED_QSORT_R 0
#define NEED_SWAP_QSORT_R 1
#define HAVE_NETPBM 1
|