Fix unamalgamated build

mongoose.c

@@ -436,6 +436,8 @@ void mg_fs_close(struct mg_fd *fd) {
 #ifdef MG_ENABLE_LINES
 #line 1 "src/fs_fat.c"
 #endif
+
+
 #if MG_ENABLE_FATFS
 #include <ff.h>
 

mongoose.h

@@ -163,11 +163,6 @@ static __inline struct tm *localtime_r(const time_t *t, struct tm *tm) {
 #endif
 
 
-#if defined(MG_ENABLE_FF) && MG_ENABLE_FF == 1
-#include <ff.h>
-#endif
-
-
 #if MG_ARCH == MG_ARCH_FREERTOS_LWIP
 
 #include <stdarg.h>

src/fs_fat.c

@@ -1,3 +1,5 @@
+#include "fs.h"
+
 #if MG_ENABLE_FATFS
 #include <ff.h>