Add first batch of tests

and fix some issues.

includes/miniffs.h

@@ -12,6 +12,10 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define MINIFFS_VERSION_MAJOR (1)
 #define MINIFFS_VERSION_MINOR (0)
 #define MINIFFS_FILENAME_LENGTH (8)
@@ -56,7 +60,7 @@ typedef struct miniffs_header_t
 /* Somewhat similar structure to the plain C FILE structure */
 typedef struct file_t
 {
-    void *private;
+    void *private_data;
     fileentry_t *fent;   /***< file linked to this structure */
     uint32_t offset;    /***< current position in the file */
 } file_t;
@@ -68,7 +72,8 @@ typedef struct file_t
 #endif
 #define MINIFFS_MAGIC MAKE4('M', 'F', 'F', 'S')
 
-enum {
+enum
+{
     MFFS_SEEK_SET,  /***< Seek from beginning of file */
     MFFS_SEEK_CUR,  /***< Seek from current position */
     MFFS_SEEK_END   /***< Seek from end of file */
@@ -123,4 +128,8 @@ void miniffs_seterror(miniffs_error_t err);
 void *miniffs_getfileaddr(miniffs_t *fs, fileentry_t *fent);
 #endif /* __miniffs_internal */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* MINIFFS_H */