env: Add environment variable flags

Currently just validates variable types as decimal, hexidecimal,
boolean, ip address, and mac address.

If the entry is not found in the env ".flags", then look in the static
one. This allows the env to override the static definitions, but prevents
the need to have every definition in the environment distracting you.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>

include/environment.h

@@ -166,6 +166,7 @@ extern void env_reloc(void);
 
 #include <env_attr.h>
 #include <env_callback.h>
+#include <env_flags.h>
 #include <search.h>
 
 extern struct hsearch_data env_htab;
@@ -189,14 +190,6 @@ int set_default_vars(int nvars, char * const vars[]);
 /* Import from binary representation into hash table */
 int env_import(const char *buf, int check);
 
-/*
- * Check if variable "item" can be changed to newval
- * When (flag & H_FORCE) is set, it does not print out any error
- * message and forces overwriting of write-once variables.
- */
-int env_change_ok(const ENTRY *item, const char *newval, enum env_op op,
-	int flag);
-
 #endif /* DO_DEPS_ONLY */
 
 #endif /* _ENVIRONMENT_H_ */