libcr51sign: Temporarily ignore deprecate functions

The code is in the process of being updated internally, but this is
blocking commits to the repo.

Change-Id: I77cb1d4f5fb8eec02c224d71d4a2e76ad893d9aa
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/subprojects/libcr51sign/src/meson.build b/subprojects/libcr51sign/src/meson.build
index c64599d..c2550e5 100644
--- a/subprojects/libcr51sign/src/meson.build
+++ b/subprojects/libcr51sign/src/meson.build
@@ -30,6 +30,10 @@
   'libcr51sign.c',
   'libcr51sign_support.c',
   dependencies: libcr51sign_pre,
+  c_args: [
+    # Temporarily ignore until updates land
+    '-Wno-error=deprecated-declarations',
+  ],
   implicit_include_directories: false,
   version: meson.project_version(),
   install: true)