glcpp: Remove xtalloc wrappers in favor of plain talloc.

Calling exit() on a memory failure probably made sense for the
standalone preprocessor, but doesn't seem too appealing as part of
the GL library.  Also, we don't use it in the main compiler.
diff --git a/src/glsl/glcpp/glcpp-parse.y b/src/glsl/glcpp/glcpp-parse.y
index 855448f..55a8d17 100644
--- a/src/glsl/glcpp/glcpp-parse.y
+++ b/src/glsl/glcpp/glcpp-parse.y
@@ -503,7 +503,7 @@
 {
 	string_list_t *list;
 
-	list = xtalloc (ctx, string_list_t);
+	list = talloc (ctx, string_list_t);
 	list->head = NULL;
 	list->tail = NULL;
 
@@ -515,8 +515,8 @@
 {
 	string_node_t *node;
 
-	node = xtalloc (list, string_node_t);
-	node->str = xtalloc_strdup (node, str);
+	node = talloc (list, string_node_t);
+	node->str = talloc_strdup (node, str);
 
 	node->next = NULL;
 
@@ -569,7 +569,7 @@
 {
 	argument_list_t *list;
 
-	list = xtalloc (ctx, argument_list_t);
+	list = talloc (ctx, argument_list_t);
 	list->head = NULL;
 	list->tail = NULL;
 
@@ -581,7 +581,7 @@
 {
 	argument_node_t *node;
 
-	node = xtalloc (list, argument_node_t);
+	node = talloc (list, argument_node_t);
 	node->argument = argument;
 
 	node->next = NULL;
@@ -638,7 +638,7 @@
 {
 	token_t *token;
 
-	token = xtalloc (ctx, token_t);
+	token = talloc (ctx, token_t);
 	token->type = type;
 	token->value.str = talloc_steal (token, str);
 
@@ -650,7 +650,7 @@
 {
 	token_t *token;
 
-	token = xtalloc (ctx, token_t);
+	token = talloc (ctx, token_t);
 	token->type = type;
 	token->value.ival = ival;
 
@@ -662,7 +662,7 @@
 {
 	token_list_t *list;
 
-	list = xtalloc (ctx, token_list_t);
+	list = talloc (ctx, token_list_t);
 	list->head = NULL;
 	list->tail = NULL;
 	list->non_space_tail = NULL;
@@ -675,8 +675,8 @@
 {
 	token_node_t *node;
 
-	node = xtalloc (list, token_node_t);
-	node->token = xtalloc_reference (list, token);
+	node = talloc (list, token_node_t);
+	node->token = talloc_reference (list, token);
 
 	node->next = NULL;
 
@@ -871,8 +871,8 @@
 	{
 		char *str;
 
-		str = xtalloc_asprintf (token, "%s%s",
-					token->value.str, other->value.str);
+		str = talloc_asprintf (token, "%s%s", token->value.str,
+				       other->value.str);
 		combined = _token_create_str (token, token->type, str);
 		combined->location = token->location;
 		return combined;
@@ -927,7 +927,7 @@
 	glcpp_parser_t *parser;
 	int language_version;
 
-	parser = xtalloc (NULL, glcpp_parser_t);
+	parser = talloc (NULL, glcpp_parser_t);
 
 	glcpp_lex_init_extra (parser, &parser->scanner);
 	parser->defines = hash_table_ctor (32, hash_table_string_hash,
@@ -1294,7 +1294,7 @@
 		token_list_t *expansion;
 		token_t *final;
 
-		str = xtalloc_strdup (parser, token->value.str);
+		str = talloc_strdup (parser, token->value.str);
 		final = _token_create_str (parser, OTHER, str);
 		expansion = _token_list_create (parser);
 		_token_list_append (expansion, final);
@@ -1330,8 +1330,8 @@
 {
 	active_list_t *node;
 
-	node = xtalloc (list, active_list_t);
-	node->identifier = xtalloc_strdup (node, identifier);
+	node = talloc (list, active_list_t);
+	node->identifier = talloc_strdup (node, identifier);
 	node->marker = marker;
 	node->next = list;
 
@@ -1481,7 +1481,7 @@
 	if (loc != NULL)
 		_check_for_reserved_macro_name(parser, loc, identifier);
 
-	macro = xtalloc (parser, macro_t);
+	macro = talloc (parser, macro_t);
 
 	macro->is_function = 0;
 	macro->parameters = NULL;
@@ -1502,7 +1502,7 @@
 
 	_check_for_reserved_macro_name(parser, loc, identifier);
 
-	macro = xtalloc (parser, macro_t);
+	macro = talloc (parser, macro_t);
 
 	macro->is_function = 1;
 	macro->parameters = talloc_steal (macro, parameters);
@@ -1628,7 +1628,7 @@
 	if (parser->skip_stack)
 		current = parser->skip_stack->type;
 
-	node = xtalloc (parser, skip_node_t);
+	node = talloc (parser, skip_node_t);
 	node->loc = *loc;
 
 	if (current == SKIP_NO_SKIP) {