Merge branch 'rj/hdr-check-gcrypt-fix'

The set of header files used by "make hdr-check" unconditionally included sha256/gcrypt.h, even when it is not used, causing the make target to fail. We now skip it when GCRYPT_SHA256 is not in use. * rj/hdr-check-gcrypt-fix: Makefile: fix 'hdr-check' when GCRYPT not installed