Handle incorrectly cased .acx file names

Fixes an issue in Tsuma Shibori (and probably other games) where .acx
file lookup fails because the actual file name contains characters which
differ in case from the name given in the code.

src/hll/ACXLoader.c

@@ -16,11 +16,13 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <errno.h>
 #include <zlib.h>
 
 #include "system4.h"
 #include "system4/string.h"
 #include "system4/acx.h"
+#include "system4/file.h"
 
 #include "hll.h"
 #include "little_endian.h"
@@ -31,8 +33,26 @@ struct acx *acx = NULL;
 
 static bool ACXLoader_Load(struct string *filename)
 {
+	int error = ACX_SUCCESS;
 	char *path = gamedir_path(filename->text);
-	acx = acx_load(path);
+	acx = acx_load(path, &error);
+
+	// XXX: Fix for games (e.g. Tsuma Shibori) that shipped with incorrectly
+	//      cased file names
+	if (error == ACX_ERROR_FILE) {
+		char *ipath = path_get_icase(path);
+		if (ipath) {
+			free(path);
+			path = ipath;
+			acx = acx_load(path, &error);
+		}
+	}
+
+	if (error == ACX_ERROR_FILE) {
+		WARNING("acx_load(\"%s\"): %s", path, strerror(errno));
+	} else if (error == ACX_ERROR_INVALID) {
+		WARNING("acx_load(\"%s\"): invalid .acx file");
+	}
 	free(path);
 	return !!acx;
 }