[openmp] Add a dependency on the separate import library (#80449)

Currently, when doing e.g. "ninja check-openmp", the check-openmp target
only depends on the target "omp", which builds the library. Thus by
doing that, the separate import library "libomp.lib", which is generated
directly from a def file, never gets created, unless one does a separate
invocation first, that builds all targets.

To fix this, make the "omp" target depend on the target for the separate
import library, whenever that is created/used.

GitOrigin-RevId: 2d2f962c9b646e809c58eccf6a46ed6b619ac252
diff --git a/runtime/src/CMakeLists.txt b/runtime/src/CMakeLists.txt
index 619d4f7..b0ecf12 100644
--- a/runtime/src/CMakeLists.txt
+++ b/runtime/src/CMakeLists.txt
@@ -306,6 +306,7 @@
         PREFIX "" SUFFIX "" OUTPUT_NAME "${LIBOMP_IMP_LIB_FILE}" LINKER_LANGUAGE ${LIBOMP_LINKER_LANGUAGE}
         STATIC_LIBRARY_OPTIONS "${CMAKE_LINK_DEF_FILE_FLAG}${CMAKE_CURRENT_BINARY_DIR}/${LIBOMPIMP_GENERATED_DEF_FILE}")
     add_dependencies(${LIBOMP_IMP_LIB_TARGET} libompimp-needed-def-file)
+    add_dependencies(omp ${LIBOMP_IMP_LIB_TARGET})
   endif()
 endif()