Fix redist glob to work on Linux

Recent Windows 10 SDKs store the UCRT redist files in a different
directory so a change was landed to scan for the right directory to
handle old and new. However the glob call used a backslash and therefore
fails on Linux. This fixes that by using os.path.join.

Bug: 915036
Change-Id: I7f71b0e9300ac33964a05881525a5eba52203859
Reviewed-on: https://chromium-review.googlesource.com/c/1377503
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#617227}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 0778ef57fb5d7b77897bb321e0fe1451ae742d62

vs_toolchain.py

@@ -218,7 +218,7 @@ def _CopyUCRTRuntime(target_dir, source_dir, target_cpu, dll_pattern, suffix):
     # Starting with the 10.0.17763 SDK the ucrt files are in a version-named
     # directory - this handles both cases.
     redist_dir = os.path.join(win_sdk_dir, 'Redist')
-    version_dirs = glob.glob(redist_dir + r'\10.*')
+    version_dirs = glob.glob(os.path.join(redist_dir, '10.*'))
     if len(version_dirs) > 0:
       version_dirs.sort(reverse=True)
       redist_dir = version_dirs[0]

win/copy_cdb_to_output.py

@@ -82,7 +82,7 @@ def _CopyCDBToOutput(output_dir, target_arch):
   # Starting with the 10.0.17763 SDK the ucrt files are in a version-named
   # directory - this handles both cases.
   redist_dir = os.path.join(win_sdk_dir, 'Redist')
-  version_dirs = glob.glob(redist_dir + r'\10.*')
+  version_dirs = glob.glob(os.path.join(redist_dir, '10.*'))
   if len(version_dirs) > 0:
     version_dirs.sort(reverse=True)
     redist_dir = version_dirs[0]