[libvirt] [PATCH] build: fix build with newer gnutls

[Eric Blake]

Building with gnutls 3.2.0 (such as shipped with current cygwin) fails
with:

rpc/virnettlscontext.c: In function 'virNetTLSSessionGetKeySize':
rpc/virnettlscontext.c:1358:5: error: implicit declaration of function 'gnutls_cipher_get_key_size' [-Wimplicit-function-declaration]

Yeah, it's stupid that gnutls broke API by moving their declaration
into a new header without including that header from the old one,
but it's easy enough to work around, all without breaking on gnutls
1.4.1 (hello RHEL 5) that lacked the new header.

* src/rpc/virnettlscontext.c (includes): Include additional header.
* configure.ac (gnutls): Check for <gnutls/crypto.h>.

Signed-off-by: Eric Blake <eblake at redhat.com>
---

Pushing under the build-breaker rule, once my testing completes
across multiple systems with various gnutls versions (1.4.1 in
RHEL5, 2.12.23 in Fedora 18, 3.2.0 in Cygwin).

 configure.ac               | 1 +
 src/rpc/virnettlscontext.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/configure.ac b/configure.ac
index 7041710..0b3d028 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1087,6 +1087,7 @@ if test "x$with_gnutls" != "xno"; then
   if test "$GNUTLS_FOUND" = "no"; then
     fail=0
     AC_CHECK_HEADER([gnutls/gnutls.h], [], [fail=1])
+    AC_CHECK_HEADERS([gnutls/crypto.h])
     AC_CHECK_LIB([gnutls], [gnutls_handshake],[], [fail=1], [-lgcrypt])

     test $fail = 0 && GNUTLS_FOUND=yes
diff --git a/src/rpc/virnettlscontext.c b/src/rpc/virnettlscontext.c
index e29c439..f2ac551 100644
--- a/src/rpc/virnettlscontext.c
+++ b/src/rpc/virnettlscontext.c
@@ -25,6 +25,9 @@
 #include <stdlib.h>

 #include <gnutls/gnutls.h>
+#if HAVE_GNULTLS_CRYPTO_H
+# include <gnutls/crypto.h>
+#endif
 #include <gnutls/x509.h>
 #include "gnutls_1_0_compat.h"

-- 
1.8.1.4