It common that in system header files, a symbol may bind to a different implementation in shared libraries depends on compilation directives.

Following is an example on Mac OS,

int stat(const char *, struct stat *) __DARWIN_INODE64(stat);

where in sys/cdefs.h, the symbol is bind to a particular alias,

#define __DARWIN_INODE64(sym) __asm("_" __STRING(sym) __DARWIN_SUF_64_BIT_INO_T)

In this case, the symbol can be bind to _stat or _stat$INODE64 in
libsystem_c.dylib