libcr51sign: build: Refactor for subproject use

This refactors the build to make it more suitable for use as a
subproject in other OpenBMC codebases.

Change-Id: I546c993d3f53c1cbe2161e5d8959373d5b12e57f
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/subprojects/libcr51sign/src/meson.build b/subprojects/libcr51sign/src/meson.build
new file mode 100644
index 0000000..e85e65c
--- /dev/null
+++ b/subprojects/libcr51sign/src/meson.build
@@ -0,0 +1,48 @@
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+libcr51sign_deps = [
+  dependency('libcrypto'),
+]
+
+libcr51sign_pre = declare_dependency(
+  include_directories: libcr51sign_includes,
+  dependencies: libcr51sign_deps)
+
+libcr51sign_lib = library(
+  'cr51sign',
+  'libcr51sign.c',
+  'libcr51sign_support.c',
+  dependencies: libcr51sign_pre,
+  implicit_include_directories: false,
+  version: meson.project_version(),
+  install: true)
+
+libcr51sign_dep = declare_dependency(
+  link_with: libcr51sign_lib,
+  dependencies: libcr51sign_pre)
+
+libcr51sign_reqs = []
+foreach dep : libcr51sign_deps
+  if dep.type_name() == 'pkgconfig'
+    libcr51sign_reqs += dep
+  endif
+endforeach
+
+import('pkgconfig').generate(
+  libcr51sign_lib,
+  name: 'libcr51sign',
+  description: 'CR51 signing verification utilities',
+  requires: libcr51sign_reqs,
+  version: meson.project_version())