Set CMake options more compactly and explicitly

Use RPM macro expressions with the ternary operator, and always set
Boolean conditionals one way or the other rather than relying on
upstream defaults.

usd.spec

@@ -352,44 +352,26 @@ extra_flags="${extra_flags-} -DTBB_SUPPRESS_DEPRECATED_MESSAGES=1"
      -DCMAKE_SKIP_RPATH=ON \
      -DCMAKE_SKIP_INSTALL_RPATH=ON \
      -DCMAKE_VERBOSE_MAKEFILE=ON \
-     -DPXR_BUILD_USDVIEW=%{?with_usdview:ON}%{?!with_usdview:OFF} \
-%if %{with documentation}
-     -DPXR_BUILD_DOCUMENTATION=TRUE \
-%endif
+     -DPXR_BUILD_USDVIEW=%{expr:%{with usdview}?"ON":"OFF"} \
+     -DPXR_BUILD_DOCUMENTATION=%{expr:%{with documentation}?"TRUE":"FALSE"} \
      -DPXR_BUILD_EXAMPLES=OFF \
      -DPXR_BUILD_TUTORIALS=OFF \
-     -DPXR_BUILD_TESTS=%{?with_test:ON}%{!?with_test:OFF} \
-%if %{with openvdb}
-     -DPXR_ENABLE_OPENVDB_SUPPORT=ON \
-%endif
+     -DPXR_BUILD_TESTS=%{expr:%{with test}?"ON":"OFF"} \
+     -DPXR_ENABLE_OPENVDB_SUPPORT=%{expr:%{with openvdb}?"ON":"OFF"} \
      -DPXR_INSTALL_LOCATION="%{_libdir}/usd/plugin" \
 %if %{with jemalloc}
      -DPXR_MALLOC_LIBRARY="%{_libdir}/libjemalloc.so" \
 %endif
-%if %{with alembic}
      -DOPENEXR_LOCATION=%{_includedir} \
-     -DPXR_BUILD_ALEMBIC_PLUGIN=ON \
-%endif
-%if %{with draco}
-     -DPXR_BUILD_DRACO_PLUGIN=ON \
-%endif
-%if %{with embree}
-     -DPXR_BUILD_EMBREE_PLUGIN=ON \
+     -DPXR_BUILD_ALEMBIC_PLUGIN=%{expr:%{with alembic}?"ON":"OFF"} \
+     -DPXR_BUILD_DRACO_PLUGIN=%{expr:%{with draco}?"ON":"OFF"} \
+     -DPXR_BUILD_EMBREE_PLUGIN=%{expr:%{with embree}?"ON":"OFF"} \
      -DEMBREE_LOCATION=%{_prefix} \
-%endif
-%if %{with ocio}
-     -DPXR_BUILD_OPENCOLORIO_PLUGIN=ON \
-%endif
-%if %{with oiio}
-     -DPXR_BUILD_OPENIMAGEIO_PLUGIN=ON \
-%endif
+     -DPXR_BUILD_OPENCOLORIO_PLUGIN=%{expr:%{with ocio}?"ON":"OFF"} \
+     -DPXR_BUILD_OPENIMAGEIO_PLUGIN=%{expr:%{with oiio}?"ON":"OFF"} \
      -DPXR_ENABLE_HDF5_SUPPORT=ON \
-%if %{with ptex}
-     -DPXR_ENABLE_PTEX_SUPPORT=ON \
-%endif
-%if %{with openshading}
-     -DPXR_ENABLE_OSL_SUPPORT=ON \
-%endif
+     -DPXR_ENABLE_PTEX_SUPPORT=%{expr:%{with ptex}?"ON":"OFF"} \
+     -DPXR_ENABLE_OSL_SUPPORT=%{expr:%{with openshading}?"ON":"OFF"} \
      -DPYTHON_EXECUTABLE=%{python3} \
      -DPYSIDE_AVAILABLE=ON \
      -DPYSIDEUICBINARY:PATH=${PWD}/uic-wrapper \