Rename FS API functions to avoid conflicts

mongoose.h

@@ -165,6 +165,7 @@ static __inline struct tm *localtime_r(const time_t *t, struct tm *tm) {
 
 #if MG_ARCH == MG_ARCH_FREERTOS_LWIP
 
+#include <ctype.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -642,19 +643,23 @@ void mg_timer_poll(int64_t current_time_ms);
 enum { MG_FS_READ = 1, MG_FS_WRITE = 2, MG_FS_DIR = 4 };
 
 // Filesystem API functions
-// stat() returns MG_FS_* flags and populates file size and modification time
-// list() calls fn() for every directory entry, allowing to list a directory
+// st() returns MG_FS_* flags and populates file size and modification time
+// ls() calls fn() for every directory entry, allowing to list a directory
+//
+// NOTE: UNIX-style shorthand names for the API functions are deliberately
+// chosen to avoid conflicts with some libraries that make macros for e.g.
+// stat(), write(), read() calls.
 struct mg_fs {
-  int (*stat)(const char *path, size_t *size, time_t *mtime);
-  void (*list)(const char *path, void (*fn)(const char *, void *), void *);
-  void *(*open)(const char *path, int flags);              // Open file
-  void (*close)(void *fd);                                 // Close file
-  size_t (*read)(void *fd, void *buf, size_t len);         // Read file
-  size_t (*write)(void *fd, const void *buf, size_t len);  // Write file
-  size_t (*seek)(void *fd, size_t offset);                 // Set file position
-  bool (*rename)(const char *from, const char *to);        // Rename
-  bool (*remove)(const char *path);                        // Delete file
-  bool (*mkd)(const char *path);                           // Create directory
+  int (*st)(const char *path, size_t *size, time_t *mtime);  // stat file
+  void (*ls)(const char *path, void (*fn)(const char *, void *), void *);
+  void *(*op)(const char *path, int flags);             // Open file
+  void (*cl)(void *fd);                                 // Close file
+  size_t (*rd)(void *fd, void *buf, size_t len);        // Read file
+  size_t (*wr)(void *fd, const void *buf, size_t len);  // Write file
+  size_t (*sk)(void *fd, size_t offset);                // Set file position
+  bool (*mv)(const char *from, const char *to);         // Rename file
+  bool (*rm)(const char *path);                         // Delete file
+  bool (*mkd)(const char *path);                        // Create directory
 };
 
 extern struct mg_fs mg_fs_posix;   // POSIX open/close/read/write/seek