Bug 31538: Make Windows builds reproducible again

Updating CMake to the latest stable version as done in the previous
commit solves the reproducibility issue only partly. We need to patch
the code that merges libc++abi.a into libc++.a to get the order in the
merged archive deterministic. The code doing the merging is:

`files = glob.glob(os.path.join(temp_directory_root, '*.o*'))`

Regarding `glob` there is following in the Python docs:

"The glob module finds all the pathnames matching a specified pattern
 according to the rules used by the Unix shell, although results are
 returned in *arbitrary* order." (emphasis mine)

(https://docs.python.org/2/library/glob.html)

projects/mingw-w64-clang/build

@@ -173,6 +173,7 @@ make -j[% c("buildconf/num_procs") %] VERBOSE=1
 
 # libcxx
 cd $builddir/libcxx
+patch -p1 < $rootdir/sort.patch
 mkdir build && cd build
 cmake -DCMAKE_BUILD_TYPE=Release \
       -DCMAKE_INSTALL_PREFIX=$distdir/[% c("arch") %]-w64-mingw32 \

projects/mingw-w64-clang/config

@@ -36,3 +36,4 @@ input_files:
   - project: llvm-mingw
     name: llvm-mingw
   - filename: mingw-winrt.patch
+  - filename: sort.patch

projects/mingw-w64-clang/sort.patch

+From 9eeb3b9ea13b25591c9081a5f05a1904d367d523 Mon Sep 17 00:00:00 2001
+From: Georg Koppen <gk@torproject.org>
+Date: Wed, 11 Sep 2019 13:25:54 +0000
+Subject: [PATCH] sorted
+
+
+diff --git a/utils/merge_archives.py b/utils/merge_archives.py
+index 58d92f0e2..597ca2471 100755
+--- a/utils/merge_archives.py
++++ b/utils/merge_archives.py
+@@ -124,7 +124,7 @@ def main():
+         execute_command_verbose([ar_exe, 'x', arc], cwd=temp_directory_root,
+                                 verbose=args.verbose)
+ 
+-    files = glob.glob(os.path.join(temp_directory_root, '*.o*'))
++    files = sorted(glob.glob(os.path.join(temp_directory_root, '*.o*')))
+     if not files:
+         print_and_exit('Failed to glob for %s' % temp_directory_root)
+     cmd = [ar_exe, 'qcs', args.output] + files
+-- 
+2.23.0
+