Fix linux_bionic build of python3

Bionic does not define AT_EACCESS, upstream uses __ANDROID__ to check
for this.

Test: build py3-cmd w/host bionic
Change-Id: I1e878bd52d6dd38a91b758d66c9869f70f40551e
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index b09204d..a24e56c 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -47,7 +47,7 @@
 
 /* On android API level 21, 'AT_EACCESS' is not declared although
  * HAVE_FACCESSAT is defined. */
-#ifdef __ANDROID__
+#ifdef __BIONIC__
 #undef HAVE_FACCESSAT
 #endif