Upgrade MinGW-based libs to MinGW-w64 v8.0.0

I've compared the crucial {msvcr*,ucrtbase}.def.in files against v7.0.0,
and they don't seem to feature any relevant changes.

See http://mingw-w64.org/doku.php/versions for the changelog; Direct3D
12 is one of the additions.

Author: kinke

azure-pipelines.yml

@@ -37,7 +37,7 @@ jobs:
     variables:
       VSINSTALLDIR: C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\
       # NB: update windows/build_mingw.sha256sums as well
-      MINGW_VER: 7.0.0
+      MINGW_VER: 8.0.0
       D_VERSION: 2.077.1
     steps:
       - template: .azure-pipelines/build-mingw-libs.yml

windows/build_mingw.bat

@@ -3,7 +3,7 @@
 set ROOT=%CD%
 mkdir "%ROOT%\artifacts"
 
-set TAG=mingw-libs-%MINGW_VER%-3
+set TAG=mingw-libs-%MINGW_VER%
 set ARTIFACT=%TAG%.zip
 set ARTIFACTPATH=%ROOT%\artifacts\%ARTIFACT%
 set GITHUB_RELEASE=https://github.com/dlang/installer/releases/download/%TAG%/%ARTIFACT%

windows/build_mingw.sha256sums

@@ -1 +1 @@
-aa20dfff3596f08a7f427aab74315a6cb80c2b086b4a107ed35af02f9496b628 mingw-w64.tar.bz2
+44c740ea6ab3924bc3aa169bad11ad3c5766c5c8459e3126d44eabb8735a5762 mingw-w64.tar.bz2

windows/mingw/buildsdk.d

@@ -164,6 +164,15 @@ void sanitizeDef(string defFile)
         if (line == "ExtractIconW@")
             return ";ExtractIconW@";
 
+        // Apparent bugs in lib32/api-ms-win-appmodel-runtime-l1-1-1.def.
+        if (line[$-1] == '@' &&
+            (line == "VerifyApplicationUserModelId@" ||
+             line == "VerifyPackageFamilyName@" ||
+             line == "VerifyPackageFullName@" ||
+             line == "VerifyPackageId@" ||
+             line == "VerifyPackageRelativeApplicationId@"))
+            return ";" ~ line;
+
         return line;
     });
 }