This is a GWT thing. We must tell it to compile for the browser you want:
-Dgwt.userAgent=safari,gecko1_8,ie10
Example:
make install-dev PREFIX=/home/yourname/ovirt-engine DEV_EXTRA_BUILD_FLAGS="-Dgwt.compiler.localWorkers=1" DEV_EXTRA_BUILD_FLAGS_GWT_DEFAULTS="-Dgwt.cssResourceStyle=pretty -Dgwt.userAgent=safari,gecko1_8,ie10" BUILD_UT=0
However, note that oVirt no longer supports IE 10, and IE 11 uses the gecko permutation. So you don't need "ie10", you can simply use:
-Dgwt.userAgent=safari,gecko1_8
Best wishes,
Greg