THRIFT-4081: appveyor retooling - added mingw64 build as a second job to the CI build process
This closes #1205
diff --git a/build/appveyor/cl_setcompiler.bat b/build/appveyor/cl_setcompiler.bat
new file mode 100644
index 0000000..b97da73
--- /dev/null
+++ b/build/appveyor/cl_setcompiler.bat
@@ -0,0 +1,63 @@
+::
+:: Licensed under the Apache License, Version 2.0 (the "License");
+:: you may not use this file except in compliance with the License.
+:: You may obtain a copy of the License at
+::
+:: http://www.apache.org/licenses/LICENSE-2.0
+::
+:: Unless required by applicable law or agreed to in writing, software
+:: distributed under the License is distributed on an "AS IS" BASIS,
+:: WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+:: See the License for the specific language governing permissions and
+:: limitations under the License.
+::
+
+::
+:: Detect the compiler edition we're building in.
+:: Set the COMPILER environment variable to one of:
+:: gcc = MinGW / MSYS2 and gcc toolchain
+:: vc100 = Visual Studio 2010
+:: vc110 = Visual Studio 2012
+:: vc120 = Visual Studio 2013
+:: vc140 = Visual Studio 2015
+:: vc150 = Visual Studio 2017
+::
+:: Honors any existing COMPILER environment variable
+:: setting instead of overwriting it, to allow it
+:: to be forced if needed.
+::
+:: Sets ERRORLEVEL to 0 if COMPILER can be determined,
+:: to 1 if it cannot.
+::
+
+IF DEFINED COMPILER (
+ ECHO [warn ] using existing environment variable COMPILER
+ EXIT /B 0
+)
+
+IF NOT "%PROFILE:~0,4%" == "MSVC" (
+ SET COMPILER=gcc
+) ELSE (
+ CALL :CHECK 16
+ IF !ERRORLEVEL! == 0 (SET COMPILER=vc100)
+ CALL :CHECK 17
+ IF !ERRORLEVEL! == 0 (SET COMPILER=vc110)
+ CALL :CHECK 18
+ IF !ERRORLEVEL! == 0 (SET COMPILER=vc120)
+ CALL :CHECK 19.00
+ IF !ERRORLEVEL! == 0 (SET COMPILER=vc140)
+ CALL :CHECK 19.10
+ IF !ERRORLEVEL! == 0 (SET COMPILER=vc150)
+)
+
+IF NOT DEFINED COMPILER (
+ ECHO [error] unable to determine the compiler edition
+ EXIT /B 1
+)
+
+ECHO [info ] detected compiler edition %COMPILER%
+EXIT /B 0
+
+:CHECK
+cl /? 2>&1 | findstr /C:"Version %1%." > nul
+EXIT /B