Merge pull request #134798 from alyssais/isGnu

lib.systems.inspect.patterns.isGnu: init

lib/systems/inspect.nix

···
     isNone         = { kernel = kernels.none; };
 
     isAndroid      = [ { abi = abis.android; } { abi = abis.androideabi; } ];
+    isGnu          = with abis; map (a: { abi = a; }) [ gnuabi64 gnu gnueabi gnueabihf ];
     isMusl         = with abis; map (a: { abi = a; }) [ musl musleabi musleabihf ];
     isUClibc       = with abis; map (a: { abi = a; }) [ uclibc uclibceabi uclibceabihf ];