diff -Naur a/higan/GNUmakefile b/higan/GNUmakefile
--- a/higan/GNUmakefile	2016-06-17 18:56:06.414883957 +0200
+++ b/higan/GNUmakefile	2016-06-17 18:56:19.075903050 +0200
@@ -4,7 +4,7 @@
 # target := loki
 # console := true
 
-flags += -I. -I.. -O3
+flags += -I. -I..
 objects := libco audio video resource
 
 # profile-guided optimization mode
@@ -31,7 +31,7 @@
 else ifeq ($(platform),macosx)
   flags += -march=native
 else ifneq ($(filter $(platform),linux bsd),)
-  flags += -march=native -fopenmp
+  flags += -fopenmp
   link += -fopenmp
   link += -Wl,-export-dynamic
   link += -lX11 -lXext
@@ -42,9 +42,9 @@
 compile = \
   $(strip \
     $(if $(filter %.c,$<), \
-      $(compiler) $(cflags) $(flags) $1 -c $< -o $@, \
+      $(compiler) $(cflags) $(flags) $(CFLAGS) $1 -c $< -o $@, \
       $(if $(filter %.cpp,$<), \
-        $(compiler) $(cppflags) $(flags) $1 -c $< -o $@ \
+        $(compiler) $(cppflags) $(flags) $(CXXFLAGS) $1 -c $< -o $@ \
       ) \
     ) \
   )

--- a/higan/target-tomoko/GNUmakefile	2016-06-17 19:10:27.729182818 +0200
+++ b/higan/target-tomoko/GNUmakefile	2016-06-17 19:14:34.034554246 +0200
@@ -45,10 +45,10 @@
 objects := $(patsubst %,obj/%.o,$(objects))
 
 obj/ruby.o: ../ruby/ruby.cpp $(call rwildcard,../ruby/)
-	$(compiler) $(rubyflags) -c $< -o $@
+	$(compiler) $(rubyflags) $(CXXFLAGS) -c $< -o $@
 
 obj/hiro.o: ../hiro/hiro.cpp $(call rwildcard,../hiro/)
-	$(compiler) $(hiroflags) -c $< -o $@
+	$(compiler) $(hiroflags) $(CXXFLAGS) -c $< -o $@
 
 obj/ui-tomoko.o: $(ui)/tomoko.cpp $(call rwildcard,$(ui)/)
 obj/ui-program.o: $(ui)/program/program.cpp $(call rwildcard,$(ui)/)
@@ -64,7 +64,7 @@
 
 # targets
 build: $(objects)
-	$(strip $(compiler) -o out/$(name) $(objects) $(link))
+	$(strip $(CXX) $(CXXFLAGS) -o out/$(name) $(objects) $(link))
 ifeq ($(platform),macosx)
 	@if [ -d out/$(name).app ]; then rm -r out/$(name).app; fi
 	mkdir -p out/$(name).app/Contents/MacOS/

--- a/icarus/GNUmakefile	2016-07-05 16:42:09.198091772 +0200
+++ b/icarus/GNUmakefile	2016-07-05 16:48:14.388351427 +0200
@@ -2,7 +2,7 @@
 include ../hiro/GNUmakefile
 
 name := icarus
-flags += -I.. -O3
+flags += -I.. $(CXXFLAGS)
 link +=
 
 ifeq ($(platform),windows)
@@ -14,7 +14,7 @@
 objects += $(if $(call streq,$(platform),windows),obj/resource.o)
 
 all: $(objects)
-	$(call unique,$(compiler) -o out/$(name) $(objects) $(link) $(hirolink))
+	$(call unique,$(compiler) -o out/$(name) $(objects) $(link) $(hirolink) $(LDFLAGS))
 ifeq ($(platform),macosx)
 	@if [ -d out/$(name).app ]; then rm -r out/$(name).app; fi
 	mkdir -p out/$(name).app/Contents/MacOS/