Fail build if thread-local data is found

Rsconscript

@@ -69,6 +69,18 @@ class Image < Builder
   end
 end
 
+class CheckThreadLocal < Builder
+  def run(options)
+    map_file = File.binread(@sources.first)
+    if map_file =~ /\.(tdata|tbss)\b/
+      $stderr.puts "Error: found thread-local data in #{@sources.first}"
+      false
+    else
+      true
+    end
+  end
+end
+
 class FontGen < Builder
   def run(options)
     if @command
@@ -88,6 +100,7 @@ end
 
 hulk_env = env "hulk", use: %w[ldc2 x86_64-elf-gcc] do |env|
   env.add_builder(FontGen)
+  env.add_builder(CheckThreadLocal)
   env.FontGen("^/src/hulk/kfont.d", "font/Hack-Regular.ttf",
               "fontgen" => fontgen_env.expand("^/fontgen"))
   env["sources"] = glob("src/hulk/**/*.d")
@@ -102,6 +115,7 @@ hulk_env = env "hulk", use: %w[ldc2 x86_64-elf-gcc] do |env|
   env["OBJCOPY"] = "x86_64-elf-objcopy"
   env.Program("^/hulk.elf", "${sources}")
   env.produces("^/hulk.elf", "^/hulk.elf.map")
+  env.CheckThreadLocal(:hulk_map_check, "^/hulk.elf.map")
   env.depends("^/hulk.elf", "src/hulk/hulk.ld")
   env["SIZE"] = "x86_64-elf-size"
   env.Size("^/hulk.size", "^/hulk.elf")
@@ -118,6 +132,7 @@ end
 
 hello_env = env "hello", use: %w[ldc2 x86_64-w64-mingw32-gcc] do |env|
   env.add_builder(Image)
+  env.add_builder(CheckThreadLocal)
   env.add_builder(HulkBinObj)
   env["sources"] = glob("src/hello/**/*.d")
   env["sources"] += glob("uefi-d/source/**/*.d")
@@ -133,6 +148,7 @@ hello_env = env "hello", use: %w[ldc2 x86_64-w64-mingw32-gcc] do |env|
   env["OBJDUMP"] = "x86_64-w64-mingw32-objdump"
   env.Program("^/HOS.EFI", "${sources}")
   env.produces("^/HOS.EFI", "^/HOS.EFI.map")
+  env.CheckThreadLocal(:hos_map_check, "^/HOS.EFI.map")
   env["SIZE"] = "x86_64-w64-mingw32-size"
   env.Size("^/HOS.size", "^/HOS.EFI")
   env.Disassemble("^/HOS.txt", "^/HOS.EFI")

src/hulk/writef.d

@@ -88,8 +88,8 @@ size_t writef(string s, va_list args, ch_out_fn ch_out)
  */
 private size_t write_hex(ulong v, bool upper, char pad, size_t width, ch_out_fn ch_out)
 {
-    static __gshared string hex_chars_lower = "0123456789abcdef";
-    static __gshared string hex_chars_upper = "0123456789ABCDEF";
+    static __gshared const(char)[16] hex_chars_lower = "0123456789abcdef";
+    static __gshared const(char)[16] hex_chars_upper = "0123456789ABCDEF";
     static __gshared char[16] buf;
     size_t i;
     do