Add stdplus dependency for pldm

pldm flight recorder feature in pldm uses stdplus::signal::block
API to block the SIGUSR1 linux signal.

Explicitly not adding this as dependency would ideally break the
compilation of pldm using subprojects.

Tested By:
1. compile pldm on ubuntu with out any openbmc - packages
2. the compilation breaks with undefined reference error
3. Put this patch in - and then recompile the code
4. now pldm compiles with out any errors.

Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: I111f3581b898c71a5e4eeee24a0bfc89c4487021
diff --git a/libpldmresponder/meson.build b/libpldmresponder/meson.build
index 7d4ae6e..9ea74a3 100644
--- a/libpldmresponder/meson.build
+++ b/libpldmresponder/meson.build
@@ -1,4 +1,4 @@
-deps = [
+libpldmresponder_deps = [
   phosphor_dbus_interfaces,
   nlohmann_json,
   sdbusplus,
@@ -49,7 +49,7 @@
   'pldmresponder',
   sources,
   version: meson.project_version(),
-  dependencies: deps,
+  dependencies: libpldmresponder_deps,
   install: true)
 
 libpldmresponder = declare_dependency(