[mutter] cogl: Fix const qualifier usage

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit bbd295ae09b0db3830addcce61a9262b81782a37
Author: Jonas Ådahl <jadahl gmail com>
Date:   Sun Jan 20 11:39:21 2019 +0100

    cogl: Fix const qualifier usage

 cogl/cogl/cogl-attribute-private.h        | 2 +-
 cogl/cogl/cogl-attribute.c                | 2 +-
 cogl/cogl/deprecated/cogl-vertex-buffer.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/cogl/cogl/cogl-attribute-private.h b/cogl/cogl/cogl-attribute-private.h
index aac4a887d..8a9b77b2c 100644
--- a/cogl/cogl/cogl-attribute-private.h
+++ b/cogl/cogl/cogl-attribute-private.h
@@ -52,7 +52,7 @@ typedef enum
 
 typedef struct _CoglAttributeNameState
 {
-  char *name;
+  const char *name;
   CoglAttributeNameID name_id;
   int name_index;
   CoglBool normalized_default;
diff --git a/cogl/cogl/cogl-attribute.c b/cogl/cogl/cogl-attribute.c
index cc1b19f45..c0c3df7db 100644
--- a/cogl/cogl/cogl-attribute.c
+++ b/cogl/cogl/cogl-attribute.c
@@ -67,7 +67,7 @@ COGL_GTYPE_DEFINE_CLASS (Attribute, attribute);
 
 static CoglBool
 validate_cogl_attribute_name (const char *name,
-                              char **real_attribute_name,
+                              const char **real_attribute_name,
                               CoglAttributeNameID *name_id,
                               CoglBool *normalized,
                               int *layer_number)
diff --git a/cogl/cogl/deprecated/cogl-vertex-buffer.c b/cogl/cogl/deprecated/cogl-vertex-buffer.c
index a853faf34..c0f0ca6e4 100644
--- a/cogl/cogl/deprecated/cogl-vertex-buffer.c
+++ b/cogl/cogl/deprecated/cogl-vertex-buffer.c
@@ -389,7 +389,7 @@ strideof (CoglAttributeType type, int n_components)
 static char *
 canonize_attribute_name (const char *attribute_name)
 {
-  char *detail_seperator = NULL;
+  const char *detail_seperator = NULL;
   int name_len;
 
   if (strncmp (attribute_name, "gl_", 3) != 0)