cc1: warning: unrecognized gcc debugging option: l
override.c:10:5: error: conflicting types for ‘fopen’
 int fopen(const char *path, const char *mode) {
     ^
In file included from override.c:4:0:
/usr/include/stdio.h:272:14: note: previous declaration of ‘fopen’ was here
 extern FILE *fopen (const char *__restrict __filename,
              ^
override.c: In function ‘open’:
override.c:25:17: error: ‘O_CREAT’ undeclared (first use in this function)
     if (oflag & O_CREAT) {
                 ^
override.c:25:17: note: each undeclared identifier is reported only once for each function it appears in
override.c:26:48: error: macro "va_arg" requires 2 arguments, but only 1 given
         ret = open(path, oflag, (mode_t)va_arg());
                                                ^
override.c:26:41: error: ‘va_arg’ undeclared (first use in this function)
         ret = open(path, oflag, (mode_t)va_arg());
                                         ^
override.c:18:11: warning: unused variable ‘original_fopen’ [-Wunused-variable]
     int (*original_fopen)(const char *, int, ...) = dlsym(RTLD_NEXT, "open");