crypto: Implement RSA algorithm by hogweed

Implement RSA algorithm by hogweed from nettle. Thus QEMU supports
a 'real' RSA backend to handle request from guest side. It's
important to test RSA offload case without OS & hardware requirement.

Signed-off-by: lei he <helei.sig11@bytedance.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
diff --git a/meson.build b/meson.build
index 9ebc00f..df7c34b 100644
--- a/meson.build
+++ b/meson.build
@@ -1121,6 +1121,7 @@
 # gcrypt over nettle for performance reasons.
 gcrypt = not_found
 nettle = not_found
+hogweed = not_found
 xts = 'none'
 
 if get_option('nettle').enabled() and get_option('gcrypt').enabled()
@@ -1158,6 +1159,15 @@
   endif
 endif
 
+gmp = dependency('gmp', required: false, method: 'pkg-config', kwargs: static_kwargs)
+if nettle.found() and gmp.found()
+  hogweed = dependency('hogweed', version: '>=3.4',
+                       method: 'pkg-config',
+                       required: get_option('nettle'),
+                       kwargs: static_kwargs)
+endif
+
+
 gtk = not_found
 gtkx11 = not_found
 vte = not_found
@@ -1769,6 +1779,7 @@
 config_host_data.set('CONFIG_TASN1', tasn1.found())
 config_host_data.set('CONFIG_GCRYPT', gcrypt.found())
 config_host_data.set('CONFIG_NETTLE', nettle.found())
+config_host_data.set('CONFIG_HOGWEED', hogweed.found())
 config_host_data.set('CONFIG_QEMU_PRIVATE_XTS', xts == 'private')
 config_host_data.set('CONFIG_MALLOC_TRIM', has_malloc_trim)
 config_host_data.set('CONFIG_STATX', has_statx)