lib: Clean up float/fpu options

ARM ABIs now have a float field. This is used as a fallback to lessen
our use of `platform.gcc.float`. I didn't know what the MIPs convention
is so I kept using `platform.gcc.float` in that case.

lib/systems/parse.nix

@@ -182,20 +182,24 @@ rec {
   types.abi = enum (attrValues abis);
 
   abis = setTypes types.openAbi {
-    android = {};
-    cygnus = {};
-    gnu = {};
-    msvc = {};
-    eabi = {};
-    androideabi = {};
-    gnueabi = {};
-    gnueabihf = {};
-    musleabi = {};
-    musleabihf = {};
-    musl = {};
-    uclibceabihf = {};
-    uclibceabi = {};
-    uclibc = {};
+    cygnus       = {};
+    msvc         = {};
+    eabi         = {};
+
+    androideabi  = {};
+    android      = {};
+
+    gnueabi      = { float = "soft"; };
+    gnueabihf    = { float = "hard"; };
+    gnu          = {};
+
+    musleabi     = { float = "soft"; };
+    musleabihf   = { float = "hard"; };
+    musl         = {};
+
+    uclibceabihf = { float = "soft"; };
+    uclibceabi   = { float = "hard"; };
+    uclibc       = {};
 
     unknown = {};
   };