Merge pull request #560 from facebookresearch/pr/schedule

use isl option to force non-negative coefficients

Author: skimo-openhub

external/isl/CMakeLists.txt

@@ -70,6 +70,7 @@ set(ISL_SOURCES
     ${ISL_SOURCE_DIR}/isl_space.c
     ${ISL_SOURCE_DIR}/isl_stream.c
     ${ISL_SOURCE_DIR}/isl_stride.c
+    ${ISL_SOURCE_DIR}/isl_system.c
     ${ISL_SOURCE_DIR}/isl_tab.c
     ${ISL_SOURCE_DIR}/isl_tab_pip.c
     ${ISL_SOURCE_DIR}/isl_tarjan.c