Use #include <foo.h> instead of #include "foo.h" in most cases.

We rely on the include path to find many of these headers.  It
especially doesn't make sense to use #include "foo.h" for headers
in the top-level include directory.

lib/util/regress/strsplit/strsplit_test.c

@@ -23,9 +23,9 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "sudo_compat.h"
-#include "sudo_fatal.h"
-#include "sudo_util.h"
+#include <sudo_compat.h>
+#include <sudo_fatal.h>
+#include <sudo_util.h>
 
 sudo_dso_public int main(int argc, char *argv[]);