bmcweb: Fix a bunch of warnings

bmcweb classically has not taken a strong opinion on warnings.  With
this commit, that policy is changing, and bmcweb will invoke the best
warnings we are able to enable, and turn on -Werror for all builds.

This is intended to reduce the likelihood of hard-to-debug situations
that the compiler coulve caught early on.

Change-Id: I57474410821e82666b3a108cfd0db7d070e8900a
Signed-off-by: Ed Tanous <ed@tanous.net>
diff --git a/include/pam_authenticate.hpp b/include/pam_authenticate.hpp
index f211a29..1469aef 100644
--- a/include/pam_authenticate.hpp
+++ b/include/pam_authenticate.hpp
@@ -25,7 +25,7 @@
     std::strcpy(pass, appPass);
 
     *resp = reinterpret_cast<pam_response*>(
-        calloc(numMsg, sizeof(struct pam_response)));
+        calloc(static_cast<size_t>(numMsg), sizeof(struct pam_response)));
 
     if (resp == nullptr)
     {