Add string literals

Rakefile

@@ -6,8 +6,6 @@
 require 'open3'
 require 'rake/clean'
 
-SYSROOT = '../eugenios/build/sysroot'
-QEMU = 'qemu-riscv32'
 STAGES = Dir.glob('boot/stage*.elna').collect { |stage| File.basename stage, '.elna' }.sort
 
 CLEAN.include 'build/boot', 'build/valid'
@@ -19,6 +17,10 @@ def compile(input, output)
   sh ENV.fetch('CC', 'gcc'), '-nostdlib', '-o', output, input
 end
 
+def run(exe)
+  ENV.fetch('QEMU', '').split << exe
+end
+
 task default: :boot
 
 desc 'Final stage'
@@ -31,9 +33,8 @@ task boot: "boot/#{STAGES.last}.elna" do |t|
   source = groupped['.elna']
 
   cat_arguments = ['cat', source]
-  compiler_arguments = [QEMU, '-L', SYSROOT, exe]
   diff_arguments = ['diff', '-Nur', '--text', expected, '-']
-  Open3.pipeline(cat_arguments, compiler_arguments, diff_arguments)
+  Open3.pipeline(cat_arguments, run(exe), diff_arguments)
 end
 
 desc 'Convert previous stage language into the current stage language'
@@ -60,8 +61,7 @@ STAGES.each do |stage|
     exe, source = t.prerequisites
 
     cat_arguments = ['cat', source]
-    compiler_arguments = [QEMU, '-L', SYSROOT, exe]
-    last_stdout, wait_threads = Open3.pipeline_r(cat_arguments, compiler_arguments)
+    last_stdout, wait_threads = Open3.pipeline_r(cat_arguments, run(exe))
 
     IO.copy_stream last_stdout, t.name
   end
@@ -70,8 +70,7 @@ STAGES.each do |stage|
     exe, source = t.prerequisites
 
     cat_arguments = ['cat', source]
-    compiler_arguments = [QEMU, '-L', SYSROOT, exe]
-    last_stdout, wait_threads = Open3.pipeline_r(cat_arguments, compiler_arguments)
+    last_stdout, wait_threads = Open3.pipeline_r(cat_arguments, run(exe))
 
     IO.copy_stream last_stdout, t.name
   end
@@ -85,8 +84,7 @@ file 'build/valid/stage1.s' => ['build/boot/stage1', 'boot/stage1.s', 'build/val
   source, exe, = t.prerequisites.partition { |prerequisite| prerequisite.end_with? '.s' }
 
   cat_arguments = ['cat', *source]
-  compiler_arguments = [QEMU, '-L', SYSROOT, *exe]
-  last_stdout, wait_threads = Open3.pipeline_r(cat_arguments, compiler_arguments)
+  last_stdout, wait_threads = Open3.pipeline_r(cat_arguments, run(exe.first))
 
   IO.copy_stream last_stdout, t.name
 end