Fix cross-compiling unclosed CMake variable (did not trigger in presubmit).

build_tools/cmake/iree_cross_compile.cmake

diff --git a/build_tools/cmake/iree_cross_compile.cmake b/build_tools/cmake/iree_cross_compile.cmake
index 4433eff..581f3d2 100644
--- a/build_tools/cmake/iree_cross_compile.cmake
+++ b/build_tools/cmake/iree_cross_compile.cmake
@@ -87,7 +87,7 @@
   iree_to_bool(_CONFIG_BUILD_PYTHON_BINDINGS "${IREE_${CONFIG_NAME}_BUILD_PYTHON_BINDINGS}")
   iree_to_bool(_CONFIG_BUILD_JAVA_BINDINGS "${IREE_${CONFIG_NAME}_BUILD_JAVA_BINDINGS}")
   iree_to_bool(_CONFIG_BUILD_EXPERIMENTAL "${IREE_${CONFIG_NAME}_BUILD_EXPERIMENTAL}")
-  iree_to_bool(_CONFIG_BUILD_TENSORFLOW_COMPILER "${IREE_${CONFIG_NAME}_BUILD_TENSORFLOW_COMPILER")
+  iree_to_bool(_CONFIG_BUILD_TENSORFLOW_COMPILER "${IREE_${CONFIG_NAME}_BUILD_TENSORFLOW_COMPILER}")
 
   # Escape semicolons in the targets list so that CMake doesn't expand them to
   # spaces.