modules/crypto/gc-*: simplify dependencies and fix stdalign.h bug

modules/crypto/gc-*: simplify dependencies and fix stdalign.h bug

stdalign problem reported by Ian Beckwith in
<http://lists.gnu.org/archive/html/bug-gnulib/2011-11/msg00238.html>.
* modules/crypto/gc-arcfour (Depends-on):
Depend conditionally on crypto/arcfour.
* modules/crypto/gc-arctwo (Depends-on):
Depend conditionally on crypto/arctwo.
* modules/crypto/gc-des (Depends-on):
Depend conditionally on crypto/des.
* modules/crypto/gc-hmac-md5 (Depends-on):
Depend conditionally on crypto/hmac-md5.
* modules/crypto/gc-hmac-sha1 (Depends-on):
Depend conditionally on crypto/hmac-sha1.
* modules/crypto/gc-md2 (Depends-on): Remove stdint, minmax.
* modules/crypto/gc-md4 (Depends-on):
Depend conditionally on crypto/md4.
* modules/crypto/gc-md5 (Depends-on):
Depend conditionally on crypto/md5.
* modules/crypto/gc-rijndael (Depends-on):
Depend conditionally on crypto/rijndael.
* modules/crypto/gc-sha1 (Depends-on):
Depend conditionally on crypto/sha1.
* modules/crypto/gc-arcfour:
* modules/crypto/gc-arctwo:
* modules/crypto/gc-des:
* modules/crypto/gc-hmac-md5:
* modules/crypto/gc-hmac-sha1:
* modules/crypto/gc-md2:
* modules/crypto/gc-md4:
* modules/crypto/gc-md5:
* modules/crypto/gc-rijndael:
* modules/crypto/gc-sha1:
(Files, Depends-on, configure.ac): Remove now-unnecessary stuff,
now that the conditional dependencies do the work for us.