libcamera: Add IPA module signing infrastructure

Add infrastructure to generate an RSA private key and sign IPA modules.
The signatures are stored in separate files with a .sign suffix.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/ipa/vimc/meson.build

@@ -1,4 +1,7 @@
-ipa = shared_module('ipa_vimc', 'vimc.cpp',
+ipa_name = 'ipa_vimc'
+
+mod = shared_module(ipa_name,
+                    'vimc.cpp',
                     name_prefix : '',
                     include_directories : [ipa_includes, libipa_includes],
                     dependencies : libcamera_dep,
@@ -6,3 +9,10 @@ ipa = shared_module('ipa_vimc', 'vimc.cpp',
                     install : true,
                     install_dir : ipa_install_dir,
                     cpp_args : '-DLICENSE="LGPL-2.1-or-later"')
+
+custom_target(ipa_name + '.so.sign',
+              input : mod,
+              output : ipa_name + '.so.sign',
+              command : [ ipa_sign, ipa_priv_key, '@INPUT@', '@OUTPUT@' ],
+              install : true,
+              install_dir : ipa_install_dir)