Move key-generation code into its own subdir.

Including mpunsafe.{h,c}, which should be an extra defence against
inadvertently using it outside the keygen library.

CMakeLists.txt

@@ -30,9 +30,8 @@ add_library(network STATIC
   be_misc.c nullplug.c errsock.c proxy.c logging.c x11disp.c)
 
 add_library(keygen STATIC
-  millerrabin.c mpunsafe.c pockle.c primecandidate.c smallprimes.c
-  sshdssg.c sshecdsag.c sshprime.c sshrsag.c
   import.c)
+add_subdirectory(keygen)
 
 add_library(agent STATIC
   sshpubk.c pageant.c aqsync.c)

keygen/CMakeLists.txt

@@ -0,0 +1,10 @@
+add_sources_from_current_dir(keygen
+  dsa.c
+  ecdsa.c
+  millerrabin.c
+  mpunsafe.c
+  pockle.c
+  prime.c
+  primecandidate.c
+  rsa.c
+  smallprimes.c)