Compiling without gallium?

Hello.

I'm having trouble compiling Mesa without gallium-egl in order to
verify some information for https://bugs.freedesktop.org/show_bug.cgi?id=72600.

The original OS package uses an unpatched Mesa compiled with the following
options:

./configure --prefix=/usr \
  --sysconfdir=/etc \
  --with-dri-driverdir=/usr/lib/xorg/modules/dri \
  --with-gallium-drivers=r300,r600,radeonsi,nouveau,svga,swrast \
  --with-dri-drivers=i915,i965,r200,radeon,nouveau,swrast \
  --with-egl-platforms=x11,drm,wayland \
  --with-llvm-shared-libs \
  --enable-gallium-llvm \
  --enable-egl \
  --enable-gallium-egl \
  --enable-shared-glapi \
  --enable-gbm \
  --enable-glx-tls \
  --enable-dri \
  --enable-glx \
  --enable-osmesa \
  --enable-gles1 \
  --enable-gles2 \
  --enable-texture-float \
  --enable-xa \
  --enable-vdpau

So, I thought I'd compile with:

./configure \
  --prefix=/opt/mesa/usr \
  --sysconfdir=/opt/mesa/etc \
  --with-dri-driverdir=/opt/mesa/usr/lib/xorg/modules/dri \
  --with-dri-drivers=i915,i965,r200,radeon,nouveau,swrast \
  --with-egl-platforms=x11,drm,wayland \
  --with-llvm-shared-libs \
  --enable-gallium-llvm \
  --enable-egl \
  --disable-gallium-egl \
  --enable-shared-glapi \
  --enable-gbm \
  --enable-glx-tls \
  --enable-dri \
  --enable-glx \
  --enable-osmesa \
  --enable-gles2 \
  --enable-texture-float \
  --enable-xa \
  --enable-vdpau

But, whereas the first build creates a file /usr/lib/egl/egl_gallium.so,
which EGL seems to use as a driver, the second build results in a complete
lack of EGL at all (there's no egl_*.so in the produced libraries).

What do I need to do to correctly compile Mesa without gallium-egl?

M