Bug#982705: openssh: FTBFS: sha2.h:57:16: error: redefinition of ‘struct _SHA2_CTX’

On Sun, Feb 14, 2021 at 12:49:29PM +0100, Andreas Henriksson wrote:
> Attached is a possibly upstreamable patch that solves our problem
> (but the base problem still exists in the code for anyone wishing to
> build with openssl disabled).

Thanks for digging into this.

How about this approach instead?  Given the choice between a
packaging-only change and one that requires another patch against
upstream, I have a slight preference for the packaging-only change as
long as it's basically reasonable, which I think this is.  It just
overrides configure's automatic detection and tells it that sha2.h isn't
available.  Builds cleanly and doesn't seem to incur any new direct
dependencies.

diff --git a/debian/rules b/debian/rules
index 73a53c309..44bac00f1 100755
--- a/debian/rules
+++ b/debian/rules
@@ -65,6 +65,10 @@ ifeq ($(DEB_HOST_ARCH_OS),hurd)
 confflags += --with-libs=-lcrypt
 endif
 
+# Avoid using libmd even if it's installed; see
+# https://bugs.debian.org/982705.
+confflags += ac_cv_header_sha2_h=false
+
 # Everything above here is common to the deb and udeb builds.
 confflags_udeb := $(confflags)
 

Thanks,