unit tests: Fix test_compiler_detection on MinGW
unit tests: Fix test_compiler_detection on MinGW

The compiler is x86_64-foo-bar-gcc/g++, so also check for that.

jeandet/meson,QuLogic/meson,jpakkane/meson,MathieuDuponchelle/meson,QuLogic/meson,jeandet/meson,ernestask/meson,ernestask/meson,pexip/meson,jpakkane/meson,ernestask/meson,MathieuDuponchelle/meson,QuLogic/meson,becm/meson,ernestask/meson,ernestask/meson,thiblahute/meson,becm/meson,jpakkane/meson,jeandet/meson,ernestask/meson,MathieuDuponchelle/meson,pexip/meson,mesonbuild/meson,QuLogic/meson,MathieuDuponchelle/meson,jeandet/meson,trhd/meson,thiblahute/meson,QuLogic/meson,trhd/meson,trhd/meson,MathieuDuponchelle/meson,jpakkane/meson,thiblahute/meson,jeandet/meson,ernestask/meson,becm/meson,trhd/meson,jpakkane/meson,MathieuDuponchelle/meson,becm/meson,mesonbuild/meson,thiblahute/meson,pexip/meson,mesonbuild/meson,becm/meson,MathieuDuponchelle/meson,jpakkane/meson,MathieuDuponchelle/meson,becm/meson,thiblahute/meson,jeandet/meson,trhd/meson,ernestask/meson,trhd/meson,pexip/meson,QuLogic/meson,thiblahute/meson,trhd/meson,pexip/meson,ernestask/meson,thiblahute/meson,becm/meson,mesonbuild/meson,QuLogic/meson,pexip/meson,MathieuDuponchelle/meson,jeandet/meson,jpakkane/meson,thiblahute/meson,trhd/meson,QuLogic/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,jeandet/meson,pexip/meson,mesonbuild/meson,jeandet/meson,thiblahute/meson,jpakkane/meson,trhd/meson,pexip/meson,becm/meson,becm/meson,becm/meson,pexip/meson,mesonbuild/meson,QuLogic/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson