fix nix hooks & patch phase

nix/default.nix

@@ -33,7 +33,7 @@ in llvmPackages.stdenv.mkDerivation (_:
   # Here we substitute GIT_HASH which is not set for cmake in nix builds.
   # Similar situation is with __DATE__ and __TIME__ macros, which are
   # set to "Jan 01 1980 00:00:00" by default.
-  patchPhase = ''
+  postPatch = ''
     substituteInPlace git_hash.cmake --replace-fail "\''${GIT_HASH}" "${rev}"
 
     local FILE_NAMES="$(find src -type f)"
@@ -71,6 +71,7 @@ in llvmPackages.stdenv.mkDerivation (_:
   # In check phase we preserve BUILD directory as
   # we need to return to it before install phase
   checkPhase = ''
+    runHook preCheck
     local BUILD_DIR=$(pwd)
     
     cd ../resources/testproject
@@ -80,6 +81,7 @@ in llvmPackages.stdenv.mkDerivation (_:
     ../build/c3c compile-run -O1 src/test_suite_runner.c3 -- ../build/c3c ./test_suite
     
     cd $BUILD_DIR
+    runHook postCheck
   '';
 
   meta = with lib; {