build-sys: fix build with libgrcypt disabled

- Move gcrypt.h include inside grcrypt-util.h.
- Allow gcrypt-util.[ch] to be compiled even without gcrypt.
This allows the logic in files using gcrypt to be simplified.

- Fix compilation of systemd-resolve without gcrypt.
systemd-resolved already supported that.

Fixes #2711.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/shared/gcrypt-util.h b/src/shared/gcrypt-util.h
index c7652c22d1..cf33b3c59c 100644
--- a/src/shared/gcrypt-util.h
+++ b/src/shared/gcrypt-util.h
@@ -19,7 +19,21 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <errno.h>
 #include <stdbool.h>
+#include <stddef.h>
+
+#ifdef HAVE_GCRYPT
+#include <gcrypt.h>
 
 void initialize_libgcrypt(bool secmem);
 int string_hashsum(const char *s, size_t len, int md_algorithm, char **out);
+#endif
+
+static inline int string_hashsum_sha224(const char *s, size_t len, char **out) {
+#ifdef HAVE_GCRYPT
+        return string_hashsum(s, len, GCRY_MD_SHA224, out);
+#else
+        return -EOPNOTSUPP;
+#endif
+}