regs: Handle HUP signals

Enable capturing and handling a HUP signal to reload configuration data.

Tested:
    Handler function called upon receiving a SIGHUP

Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
Change-Id: I41d136ede5f2a4c0bf595ee58993a4408f153013
diff --git a/phosphor-regulators/src/meson.build b/phosphor-regulators/src/meson.build
index 1bf0fb5..9d82033 100644
--- a/phosphor-regulators/src/meson.build
+++ b/phosphor-regulators/src/meson.build
@@ -43,7 +43,8 @@
         libi2c_dep,
         phosphor_logging,
         sdbusplus,
-        sdeventplus
+        sdeventplus,
+        stdplus
     ],
     link_with: phosphor_regulators_library,
     implicit_include_directories: false,