diff --git a/compiler/Makefile b/compiler/Makefile
index 256fc1a95..5a9ec728a 100644
--- a/compiler/Makefile
+++ b/compiler/Makefile
@@ -5,8 +5,6 @@ PARALLEL_EXECUTION_ENABLED=OFF
 CC_COMPILER=
 CXX_COMPILER=
 
-EXTERNAL_HEADERS=include/boost-single-header/outcome.hpp
-
 KEYSETCACHEDEV=/tmp/KeySetCache
 KEYSETCACHECI=../KeySetCache
 
@@ -63,9 +61,6 @@ $(BUILD_DIR)/configured.stamp:
 	-DPython3_EXECUTABLE=${Python3_EXECUTABLE}
 	touch $@
 
-include/boost-single-header/outcome.hpp:
-	wget https://github.com/ned14/outcome/raw/master/single-header/outcome.hpp -O $@
-
 build-initialized: $(EXTERNAL_HEADERS) $(BUILD_DIR)/configured.stamp
 
 doc: build-initialized