In libraries/base/include/HsBase.h, there is
INLINE int __hsposix_SIG_BLOCK() { return SIG_BLOCK; }
INLINE int __hsposix_SIG_UNBLOCK() { return SIG_SETMASK; }
INLINE int __hsposix_SIG_SETMASK() { return SIG_UNBLOCK; }
That's not intentional, is it?