CI: build mingw in Debug mode

That way we have a build that tests that assert statements compile.
MinGW is chosen since it does not run unit tests.

azure-pipelines.yml

@@ -68,18 +68,21 @@ jobs:
     strategy:
       matrix:
         GCC:
+          BUILD_TYPE: Release
           C_COMPILER: gcc
           CXX_COMPILER: g++
           EXTRA_PACKAGES:
           EXTRA_INSTALLS:
           TOOLCHAIN_FILE:
         Clang:
+          BUILD_TYPE: Release
           C_COMPILER: clang
           CXX_COMPILER: clang++
           EXTRA_PACKAGES:
           EXTRA_INSTALLS:
           TOOLCHAIN_FILE:
         Mingw:
+          BUILD_TYPE: Debug
           C_COMPILER: x86_64-w64-mingw32-gcc
           CXX_COMPILER: x86_64-w64-mingw32-g++
           EXTRA_PACKAGES: gcc-mingw-w64-x86-64 g++-mingw-w64-x86-64 mingw-w64-x86-64-dev
@@ -120,7 +123,7 @@ jobs:
     - bash: |
         set -e
         cmake --version
-        cmake -G "Ninja" -Wdev -Wdeprecated -DCMAKE_TOOLCHAIN_FILE=$(TOOLCHAIN_FILE) -DCMAKE_C_COMPILER=$(C_COMPILER) -DCMAKE_CXX_COMPILER=$(CXX_COMPILER) -DUSE_PRECOMPILED_HEADER=0 -DUSE_WERROR=1 -DBE_VERBOSE=1 -DBUILD_DUMMY_APP=1 -DBUILD_TESTS=1 -DCMAKE_BUILD_TYPE=Release -H. -Bbuild
+        cmake -G "Ninja" -Wdev -Wdeprecated -DCMAKE_TOOLCHAIN_FILE=$(TOOLCHAIN_FILE) -DCMAKE_C_COMPILER=$(C_COMPILER) -DCMAKE_CXX_COMPILER=$(CXX_COMPILER) -DUSE_PRECOMPILED_HEADER=0 -DUSE_WERROR=1 -DBE_VERBOSE=1 -DBUILD_DUMMY_APP=1 -DBUILD_TESTS=1 -DCMAKE_BUILD_TYPE=$(BUILD_TYPE) -H. -Bbuild
         cmake --build build -- -j`nproc`
       displayName: 'Build'
     - bash: |