https://bugs.gentoo.org/904169
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -309,7 +309,7 @@
 CORE_CFLAGS += -Wextra
 CORE_CFLAGS += -std=gnu11
 
-CXXFLAGS += -std=gnu++14 -fno-exceptions -fno-rtti
+CXXFLAGS += -std=gnu++17 -fno-exceptions -fno-rtti
 CXXFLAGS += -Wall
 CXXFLAGS += -fno-omit-frame-pointer
 CXXFLAGS += -ggdb3
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -339,7 +339,7 @@
 	$(BUILD)
 
 $(OUTPUT)test-llvm.bin:
-	$(BUILDXX) -std=gnu++14 				\
+	$(BUILDXX) -std=gnu++17 				\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		$(shell $(LLVM_CONFIG) --libs)			\
@@ -347,12 +347,12 @@
 		> $(@:.bin=.make.output) 2>&1
 
 $(OUTPUT)test-llvm-version.bin:
-	$(BUILDXX) -std=gnu++14					\
+	$(BUILDXX) -std=gnu++17					\
 		-I$(shell $(LLVM_CONFIG) --includedir)		\
 		> $(@:.bin=.make.output) 2>&1
 
 $(OUTPUT)test-clang.bin:
-	$(BUILDXX) -std=gnu++14					\
+	$(BUILDXX) -std=gnu++17					\
 		-I$(shell $(LLVM_CONFIG) --includedir) 		\
 		-L$(shell $(LLVM_CONFIG) --libdir)		\
 		-lclang-cpp $(shell $(LLVM_CONFIG) --libs)	\