move git_default_* variables to ident.c

There's no reason anybody outside of ident.c should access
these directly (they should use the new accessors which make
sure the variables are initialized), so we can make them
file-scope statics.

While we're at it, move user_ident_explicitly_given into
ident.c; while still globally visible, it makes more sense
to reside with the ident code.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

cache.h

@@ -1142,9 +1142,6 @@ struct config_include_data {
 #define CONFIG_INCLUDE_INIT { 0 }
 extern int git_config_include(const char *name, const char *value, void *data);
 
-#define MAX_GITNAME (1000)
-extern char git_default_email[MAX_GITNAME];
-extern char git_default_name[MAX_GITNAME];
 #define IDENT_NAME_GIVEN 01
 #define IDENT_MAIL_GIVEN 02
 #define IDENT_ALL_GIVEN (IDENT_NAME_GIVEN|IDENT_MAIL_GIVEN)

environment.c

@@ -11,9 +11,6 @@
 #include "refs.h"
 #include "fmt-merge-msg.h"
 
-char git_default_email[MAX_GITNAME];
-char git_default_name[MAX_GITNAME];
-int user_ident_explicitly_given;
 int trust_executable_bit = 1;
 int trust_ctime = 1;
 int has_symlinks = 1;

ident.c

@@ -7,7 +7,11 @@
  */
 #include "cache.h"
 
+#define MAX_GITNAME (1000)
+static char git_default_name[MAX_GITNAME];
+static char git_default_email[MAX_GITNAME];
 static char git_default_date[50];
+int user_ident_explicitly_given;
 
 #ifdef NO_GECOS_IN_PWENT
 #define get_gecos(ignored) "&"