legacy-support: unable to build on Tiger

[kencu (Ken)]

The new head of the legacysupport commit tree is no longer able to build on Tiger, as it uses defines that don't exist on Tiger.

cc -c -Iinclude -Os -Wall -fPIC src/atcalls.c -o src/atcalls.dl.o
In file included from src/atcalls.c:57:
include/dirent.h:30: error: parse error before '__DARWIN_ALIAS_I'
include/dirent.h:30: warning: type defaults to 'int' in declaration of '__DARWIN_ALIAS_I'
include/dirent.h:30: warning: parameter names (without types) in function declaration
include/dirent.h:30: warning: data definition has no type or storage class
make: *** [Makefile:222: src/atcalls.dl.o] Error 1

It's easy enough to #ifndef something in, but making sure it still works as expected is another issue.

Please do not update the release version (at least) of legacysupport until this is resolved.

[kencu (Ken)]

I added a blank definition for the missing #define to dirent.h, and that gets Tiger past that hiccup. Now it fails as per #60147, so at least we have them all in the same boat. This issue seems closeable.