Repair appveyor

Signed-off-by: Vadim Markovtsev <vadim@sourced.tech>

appveyor.yml

@@ -8,15 +8,13 @@ environment:
   GOPATH: c:\gopath
 
 install:
-  - appveyor-retry choco install --allow-empty-checksums make
-  - c:\msys64\usr\bin\pacman --noconfirm --needed -S mingw-w64-x86_64-toolchain
   - curl -SLko protoc.zip https://github.com/google/protobuf/releases/download/v3.5.1/protoc-3.5.1-win32.zip
   - 7z e protoc.zip
   - move protoc.exe C:\msys64\mingw64\bin
 
 build_script:
+  - set PATH=C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin;C:\msys64\usr\bin;C:\msys64\mingw64\bin;%PATH%
   - set PATH=%PATH:C:\Program Files\Git\usr\bin;=%
-  - set PATH=C:\msys64\mingw64\bin;%PATH%
   - cd %GOPATH%\src\gopkg.in\src-d\hercules.v4
   - set DISABLE_TENSORFLOW=1
   - make

Makefile

@@ -22,8 +22,8 @@ internal/pb/pb.pb.go: internal/pb/pb.proto ${GOPATH}/bin/protoc-gen-gogo
 	PATH=${PATH}:${GOPATH}/bin protoc --gogo_out=internal/pb --proto_path=internal/pb internal/pb/pb.proto
 else
 internal/pb/pb.pb.go: internal/pb/pb.proto ${GOPATH}/bin/protoc-gen-gogo.exe
-	set "PATH=${PATH};${GOPATH}\bin" && \
-	call protoc --gogo_out=internal/pb --proto_path=internal/pb internal/pb/pb.proto
+	export PATH="${PATH};${GOPATH}\bin" && \
+	protoc --gogo_out=internal/pb --proto_path=internal/pb internal/pb/pb.proto
 endif
 
 internal/pb/pb_pb2.py: internal/pb/pb.proto