diff --git a/MultiSource/Benchmarks/DOE-ProxyApps-C++/miniFE/CMakeLists.txt b/MultiSource/Benchmarks/DOE-ProxyApps-C++/miniFE/CMakeLists.txt
index 6a55a7f..e6afd61 100644
--- a/MultiSource/Benchmarks/DOE-ProxyApps-C++/miniFE/CMakeLists.txt
+++ b/MultiSource/Benchmarks/DOE-ProxyApps-C++/miniFE/CMakeLists.txt
@@ -1,4 +1,4 @@
-list(APPEND CXXFLAGS -I. -DMINIFE_SCALAR=double  -DMINIFE_LOCAL_ORDINAL=int -DMINIFE_GLOBAL_ORDINAL=int -DMINIFE_CSR_MATRIX -DREDSTORM -D_XOPEN_SOURCE=700) # -DREDSTORM for mkdir
+list(APPEND CXXFLAGS -I. -DMINIFE_SCALAR=double  -DMINIFE_LOCAL_ORDINAL=int -DMINIFE_GLOBAL_ORDINAL=int -DMINIFE_CSR_MATRIX -DREDSTORM) # -DREDSTORM for mkdir
 list(APPEND LDFLAGS -lm)
 set(RUN_OPTIONS -nx 64 -ny 64 -nz 64)
 llvm_multisource(miniFE)