qga: Fix compiler warnings (missing format attribute, wrong format strings)

gcc 4.8.2 reports this warning when extra warnings are enabled (-Wextra):

  CC    qga/commands.o
qga/commands.c: In function ‘slog’:
qga/commands.c:28:5: error:
 function might be possible candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
     ^

gcc 4.8.2 reports this warning when slog is declared with the
gnu_printf format attribute:

qga/commands-posix.c: In function ‘qmp_guest_file_open’:
qga/commands-posix.c:404:5: warning:
 format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int64_t’ [-Wformat=]
     slog("guest-file-open, handle: %d", handle);
     ^

On 32 bit hosts there are three more warnings which are also fixed here.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

qga/commands-posix.c

@@ -401,7 +401,7 @@ int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, E
         return -1;
     }
 
-    slog("guest-file-open, handle: %d", handle);
+    slog("guest-file-open, handle: %" PRId64, handle);
     return handle;
 }
 
@@ -410,7 +410,7 @@ void qmp_guest_file_close(int64_t handle, Error **err)
     GuestFileHandle *gfh = guest_file_handle_find(handle, err);
     int ret;
 
-    slog("guest-file-close called, handle: %ld", handle);
+    slog("guest-file-close called, handle: %" PRId64, handle);
     if (!gfh) {
         return;
     }
@@ -451,7 +451,7 @@ struct GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
     read_count = fread(buf, 1, count, fh);
     if (ferror(fh)) {
         error_setg_errno(err, errno, "failed to read file");
-        slog("guest-file-read failed, handle: %ld", handle);
+        slog("guest-file-read failed, handle: %" PRId64, handle);
     } else {
         buf[read_count] = 0;
         read_data = g_malloc0(sizeof(GuestFileRead));
@@ -496,7 +496,7 @@ GuestFileWrite *qmp_guest_file_write(int64_t handle, const char *buf_b64,
     write_count = fwrite(buf, 1, count, fh);
     if (ferror(fh)) {
         error_setg_errno(err, errno, "failed to write to file");
-        slog("guest-file-write failed, handle: %ld", handle);
+        slog("guest-file-write failed, handle: %" PRId64, handle);
     } else {
         write_data = g_malloc0(sizeof(GuestFileWrite));
         write_data->count = write_count;

qga/guest-agent-core.h

@@ -29,7 +29,7 @@ GACommandState *ga_command_state_new(void);
 bool ga_logging_enabled(GAState *s);
 void ga_disable_logging(GAState *s);
 void ga_enable_logging(GAState *s);
-void slog(const gchar *fmt, ...);
+void GCC_FMT_ATTR(1, 2) slog(const gchar *fmt, ...);
 void ga_set_response_delimited(GAState *s);
 bool ga_is_frozen(GAState *s);
 void ga_set_frozen(GAState *s);