locate: use g_utf8_casefold() instead of string_toupper()

string_toupper() and strDupToUpper() were not able to deal with
character sets other than US-ASCII.  Use GLib's g_utf8_casefold()
for strings.

src/utils.c

@@ -24,7 +24,6 @@
 
 #include <assert.h>
 #include <string.h>
-#include <ctype.h>
 #include <sys/types.h>
 #include <pwd.h>
 #include <fcntl.h>
@@ -45,23 +44,6 @@ char *myFgets(char *buffer, int bufferSize, FILE * fp)
 	return ret;
 }
 
-char *string_toupper(char *str)
-{
-	int i = strlen(str);
-	char *ret = str;
-
-	for (; --i >= 0; ++str)
-		*str = toupper((int)(*str));
-
-	return ret;
-
-}
-
-char *strDupToUpper(char *str)
-{
-	return string_toupper(xstrdup(str));
-}
-
 void stripReturnChar(char *string)
 {
 	while (string && (string = strchr(string, '\n'))) {