Windows: Registry based configuration

Load configuration data in the registry into a krb5_config_section.
Each registry key corresponds to a krb5_config_section and each
registry value becomes a bound string value.

The set of values contained in the root Heimdal registry key is
treated as if they were defined in the [libdefaults] section.

E.g. the configuration file:

[libdefaults]
foo = bar

[Foo]
x = y
y = {
  baz = quux
}

is equivalent to the registry keys:

[HKEY_CURRENT_USER\Software\Heimdal]
"foo"="bar"

[HKEY_CURRENT_USER\Software\Heimdal\Foo]
"x"="y"

[HKEY_CURRENT_USER\Software\Heimdal\Foo\y]
"baz"="quux"

lib/krb5/NTMakefile

@@ -48,6 +48,7 @@ libkrb5_OBJS =			\
 	$(OBJ)\changepw.obj		    \
 	$(OBJ)\codec.obj		    \
 	$(OBJ)\config_file.obj		    \
+	$(OBJ)\config_reg.obj		    \
 	$(OBJ)\convert_creds.obj	    \
 	$(OBJ)\constants.obj		    \
 	$(OBJ)\context.obj		    \
@@ -190,6 +191,7 @@ dist_libkrb5_la_SOURCES =			\
 	changepw.c				\
 	codec.c					\
 	config_file.c				\
+	config_reg.c				\
 	convert_creds.c				\
 	constants.c				\
 	context.c				\