cbqn: remove vendoring using builtin capabilities

The makefile (counterintuitively) checks src/gen/customRuntime to see if
the bytecode is up to date. By simply touch(1)-ing it, we can save
maintaining a patch.

pkgs/development/interpreters/bqn/cbqn/001-remove-vendoring.diff

@@ -1,15 +0,0 @@
-diff --git a/makefile b/makefile
-index a5f3d75..f617e25 100644
---- a/makefile
-+++ b/makefile
-@@ -109,9 +109,7 @@ ${bd}/%.o: src/builtins/%.c
- 
- 
- src/gen/customRuntime:
--	@echo "Copying precompiled bytecode from the bytecode branch"
--	git checkout remotes/origin/bytecode src/gen/{compiler,formatter,runtime0,runtime1,src}
--	git reset src/gen/{compiler,formatter,runtime0,runtime1,src}
-+	@echo "src/gen/ files retrieved externally"
- ${bd}/load.o: src/gen/customRuntime
- 
- -include $(bd)/*.d

pkgs/development/interpreters/bqn/cbqn/default.nix

@@ -29,23 +29,18 @@ stdenv.mkDerivation rec {
 
   dontConfigure = true;
 
-  patches = [
-    # self-explaining
-    ./001-remove-vendoring.diff
-  ];
-
   postPatch = ''
     sed -i '/SHELL =.*/ d' makefile
   '';
 
-  preBuild =
-    if genBytecode
-    then ''
-      ${bqn-path} genRuntime ${mbqn-source}
-    ''
-    else ''
-      cp ${cbqn-bytecode-files}/src/gen/{compiler,formatter,runtime0,runtime1,src} src/gen/
-    '';
+  preBuild = ''
+    # inform make we are providing the runtime ourselves
+    touch src/gen/customRuntime
+  '' + (if genBytecode then ''
+    ${bqn-path} genRuntime ${mbqn-source}
+  '' else ''
+    cp ${cbqn-bytecode-files}/src/gen/{compiler,formatter,runtime0,runtime1,src} src/gen/
+  '');
 
   makeFlags = [
     "CC=${stdenv.cc.targetPrefix}cc"