Replace bogus mingw64/32bit CI job with actual 32bit build

mingw64 is not multilib-capable, so using an x86_64-mingw with BINARY=32 was not going to work anyway (but build passed while BINARY=32 was ignored).

appveyor.yml

@@ -38,7 +38,8 @@ environment:
     - COMPILER: MinGW64-gcc-7.2.0-mingw
       DYNAMIC_ARCH: OFF
       WITH_FORTRAN: ignore
-    - COMPILER: MinGW64-gcc-7.2.0
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      COMPILER: MinGW-gcc-6.3.0-32   
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       COMPILER: MinGW-gcc-5.3.0
       WITH_FORTRAN: ignore
@@ -62,10 +63,10 @@ before_build:
   - set PATH=%PATH:C:\Program Files\Git\usr\bin;=%
   - if [%COMPILER%]==[MinGW-gcc-5.3.0] set PATH=C:\MinGW\bin;C:\msys64\usr\bin;C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin;%PATH%
   - if [%COMPILER%]==[MinGW64-gcc-7.2.0-mingw] set PATH=C:\MinGW\bin;C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin;%PATH%
-  - if [%COMPILER%]==[MinGW64-gcc-7.2.0] set PATH=C:\msys64\usr\bin;C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin;%PATH%
+  - if [%COMPILER%]==[MinGW-gcc-6.3.0-32] set PATH=C:\msys64\usr\bin;C:\mingw-w64\i686-6.3.0-posix-dwarf-rt_v5-rev1\mingw64\bin;%PATH%
   - if [%COMPILER%]==[cl] cmake -G "Visual Studio 15 2017 Win64" ..
   - if [%COMPILER%]==[MinGW64-gcc-7.2.0-mingw] cmake -G "MinGW Makefiles" -DNOFORTRAN=1 ..
-  - if [%COMPILER%]==[MinGW64-gcc-7.2.0] cmake -G "MSYS Makefiles"  -DBINARY=32 -DNOFORTRAN=1 ..
+  - if [%COMPILER%]==[MinGW-gcc-6.3.0-32] cmake -G "MSYS Makefiles" -DNOFORTRAN=1 ..
   - if [%COMPILER%]==[MinGW-gcc-5.3.0] cmake -G "MSYS Makefiles" -DNOFORTRAN=1 ..
   - if [%WITH_FORTRAN%]==[no] cmake -G "Ninja" -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_C_COMPILER=clang-cl -DMSVC_STATIC_CRT=ON ..
   - if [%WITH_FORTRAN%]==[yes] cmake -G "Ninja" -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_C_COMPILER=clang-cl -DCMAKE_Fortran_COMPILER=flang -DBUILD_WITHOUT_LAPACK=no -DNOFORTRAN=0 ..