Add script for removing <CR> on windows.

This caused bad stuff to be generated on windows, specifically
the amalg file. We cause totally strip <CR> from files on windows
using this script.

build_win.bat

@@ -98,6 +98,7 @@ for %%f in (src\core\*.c) do (
     set "amalg_files=!amalg_files! %%f"
 )
 janet.exe tools\amalg.janet src\core\util.h src\core\state.h src\core\gc.h src\core\vector.h src\core\fiber.h src\core\regalloc.h src\core\compile.h src\core\emit.h src\core\symcache.h %amalg_files% build\core_image.c > build\janet.c
+janet.exe tools\removecr.janet build\janet.c
 
 echo === Successfully built janet.exe for Windows ===
 echo === Run 'build_win test' to run tests. ==
@@ -137,6 +138,7 @@ exit /b 0
 :DIST
 mkdir dist
 janet.exe tools\gendoc.janet > dist\doc.html
+janet.exe tools\removecr.janet dist\doc.html
 
 copy build\janet.c dist\janet.c
 copy janet.exe dist\janet.exe

tools/amalg.janet

@@ -9,4 +9,4 @@
 
 # Body
 (each path (tuple/slice (dyn :args) 1)
-  (print (slurp path)))
+  (print (slurp path :r)))

tools/removecr.janet

@@ -0,0 +1,9 @@
+# Remove carriage returns from file. Since piping things on 
+# windows may add bad line endings, we can just force removal
+# with this script.
+(def fname ((dyn :args) 1))
+(with [f (file/open fname :rb+)]
+  (def source (:read f :all))
+  (def new-source (string/replace-all "\r" "" source))
+  (:seek f :set 0)
+  (:write f new-source))