appveyor: Move MSVC dist builds to their own builder

In the long run we want to separate out the dist builders from the test
builders. This provides us leeway to expand the dist builders with more tools
(e.g. Cargo and the RLS) without impacting cycle times.

Currently the Travis dist builders double-up the platforms they provide builds
for, so I figured we could try that out for MSVC as well. This commit adds a new
AppVeyor builder which runs a dist for all the MSVC targets:

* x86_64-pc-windows-msvc
* i686-pc-windows-msvc
* i586-pc-windows-msvc

If this takes too long and/or times out we'll need to split this up. In any case
we're going to need more capacity from AppVeyor no matter what becaue the two
pc-windows-gnu targets can't cross compile so we need at least 2 more builders
no matter what.

appveyor.yml

@@ -5,17 +5,15 @@ environment:
     secure: 1UkmbiDd15tWtYbMm5O2Uqm0b0Ur8v1MoSlydxl4ojcroPeerRMlUges0l57py8c
   SCCACHE_DIGEST: f808afabb4a4eb1d7112bcb3fa6be03b61e93412890c88e177c667eb37f46353d7ec294e559b16f9f4b5e894f2185fe7670a0df15fd064889ecbd80f0c34166c
   matrix:
-  # 32/64 bit MSVC
+  # 32/64 bit MSVC tests
   - MSYS_BITS: 64
-    RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-extended
-    SCRIPT: python x.py test && python x.py dist
-    DEPLOY: 1
+    RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc
+    SCRIPT: python x.py test
   - MSYS_BITS: 32
-    RUST_CONFIGURE_ARGS: --build=i686-pc-windows-msvc --target=i586-pc-windows-msvc --enable-extended
-    SCRIPT: python x.py test --host i686-pc-windows-msvc --target i686-pc-windows-msvc && python x.py dist
-    DEPLOY: 1
+    RUST_CONFIGURE_ARGS: --build=i686-pc-windows-msvc --target=i586-pc-windows-msvc
+    SCRIPT: python x.py test --host i686-pc-windows-msvc --target i686-pc-windows-msvc
 
-  # MSVC cargotest
+  # MSVC aux tests
   - MSYS_BITS: 64
     RUST_CHECK_TARGET: check-aux
     RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc
@@ -44,16 +42,40 @@ environment:
   # And as a final point of note, the 32-bit MinGW build using the makefiles do
   # *not* use debug assertions and llvm assertions. This is because they take
   # too long on appveyor and this is tested by rustbuild below.
+  - MSYS_BITS: 32
+    RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
+    SCRIPT: python x.py test
+    MINGW_URL: https://s3.amazonaws.com/rust-lang-ci
+    MINGW_ARCHIVE: i686-4.9.2-release-win32-dwarf-rt_v4-rev4.7z
+    MINGW_DIR: mingw32
+  - MSYS_BITS: 64
+    SCRIPT: python x.py test
+    RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu
+    MINGW_URL: https://s3.amazonaws.com/rust-lang-ci
+    MINGW_ARCHIVE: x86_64-4.9.2-release-win32-seh-rt_v4-rev4.7z
+    MINGW_DIR: mingw64
+
+  # 32/64 bit MSVC and GNU deployment
+  - RUST_CONFIGURE_ARGS: >
+      --build=x86_64-pc-windows-msvc
+      --enable-extended
+    SCRIPT: python x.py dist
+    DEPLOY: 1
+  - RUST_CONFIGURE_ARGS: >
+      --build=i686-pc-windows-msvc
+      --target=i586-pc-windows-msvc
+      --enable-extended
+    SCRIPT: python x.py dist
+    DEPLOY: 1
   - MSYS_BITS: 32
     RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu --enable-extended
-    SCRIPT: python x.py test && python x.py dist
+    SCRIPT: python x.py dist
     MINGW_URL: https://s3.amazonaws.com/rust-lang-ci
     MINGW_ARCHIVE: i686-4.9.2-release-win32-dwarf-rt_v4-rev4.7z
     MINGW_DIR: mingw32
     DEPLOY: 1
-
   - MSYS_BITS: 64
-    SCRIPT: python x.py test && python x.py dist
+    SCRIPT: python x.py dist
     RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu --enable-extended
     MINGW_URL: https://s3.amazonaws.com/rust-lang-ci
     MINGW_ARCHIVE: x86_64-4.9.2-release-win32-seh-rt_v4-rev4.7z
@@ -83,12 +105,15 @@ install:
   # file exists in there (which it doesn't by default).
   - if defined MINGW_URL appveyor DownloadFile %MINGW_URL%/%MINGW_ARCHIVE%
   - if defined MINGW_URL 7z x -y %MINGW_ARCHIVE% > nul
-  - if defined MINGW_URL set PATH=C:\Python27;%CD%\%MINGW_DIR%\bin;C:\msys64\usr\bin;%PATH%
-  - if defined MINGW_URL copy C:\Python27\python.exe C:\Python27\python2.7.exe
+  - if defined MINGW_URL set PATH=%CD%\%MINGW_DIR%\bin;C:\msys64\usr\bin;%PATH%
 
   # Otherwise pull in the MinGW installed on appveyor
   - if NOT defined MINGW_URL set PATH=C:\msys64\mingw%MSYS_BITS%\bin;C:\msys64\usr\bin;%PATH%
 
+  # Prefer the "native" Python as LLVM has trouble building with MSYS sometimes
+  - copy C:\Python27\python.exe C:\Python27\python2.7.exe
+  - set PATH=C:\Python27;%PATH%
+
   # Download and install sccache
   - appveyor DownloadFile https://api.pub.build.mozilla.org/tooltool/sha512/%SCCACHE_DIGEST%
   - mv %SCCACHE_DIGEST% sccache.tar.bz2