treewide: Fix various compiler warnings

LTO is currently hiding these warnings.

Change-Id: I09560dfbb150f43d58f472e7592fc0c072e3cc29
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/selutility.cpp b/selutility.cpp
index 8d327d2..3473814 100644
--- a/selutility.cpp
+++ b/selutility.cpp
@@ -81,7 +81,7 @@
 
 int convert(const std::string_view& str, int base = 10)
 {
-    int ret;
+    int ret = 0;
     std::from_chars(str.data(), str.data() + str.size(), ret, base);
     return ret;
 }