diff '--color=auto' -ruN fasthenry-3.0wr.orig/src/fasthenry/mk_syscfg.inc fasthenry-3.0wr/src/fasthenry/mk_syscfg.inc
--- fasthenry-3.0wr.orig/src/fasthenry/mk_syscfg.inc	2024-01-06 21:27:26.000000000 +0100
+++ fasthenry-3.0wr/src/fasthenry/mk_syscfg.inc	2025-10-25 23:07:57.993608185 +0200
@@ -7,24 +7,7 @@
 # is 4.8 or later.  This should also work for macOS clang on Intel
 # Macs.
 
-ifeq "$(shell uname -m)" "x86_64"
-HAVX = 0
-CC := gcc
-GCC_major := "`gcc -dumpversion | cut -f1 -d.`"
-GCC_minor := "`gcc -dumpversion | cut -f2 -d.`"
-CHKMAJG := $(shell expr $(GCC_major) ">" 4)
-CHKMAJE := $(shell expr $(GCC_major) "=" 4)
-ifeq "$(CHKMAJG)" "1"
-    HAVX = 1
-else
-ifeq "$(CHKMAJE)" "1"
-CHKMINGE := $(shell expr $(GCC_minor) ">=" 8)
-ifeq "$(CHKMINGE)" "1"
-    HAVX = 1
-endif
-endif
-endif
-endif
+# We need HAVX=(0|1) to be supplied by portage
 
 # If you build with AVX enabled, and run on a system that does not
 # have AVX, the program will crash.  If is not likely that you would
@@ -33,11 +16,13 @@
 # There seems to be no way to accommodate the presence/absence of AVX
 # at run-time nicely.
 
+# -mavx should come from CFLAGS if needed
+
 ifeq "$(HAVX)" "1"
-    MAVX = -mavx -DWITH_AVX
+    MAVX = -DWITH_AVX
 endif
 
-CFLAGS = -O3 -DFOUR $(MAVX) 
+CFLAGS += -DFOUR $(MAVX)
 
 # For debugging.
 #CFLAGS = -O -g -DFOUR $(MAVX)
diff '--color=auto' -ruN fasthenry-3.0wr.orig/src/sparse/Makefile fasthenry-3.0wr/src/sparse/Makefile
--- fasthenry-3.0wr.orig/src/sparse/Makefile	2025-10-25 23:06:07.850948286 +0200
+++ fasthenry-3.0wr/src/sparse/Makefile	2025-10-25 23:06:26.660231747 +0200
@@ -4,7 +4,7 @@
 #  UC Berkeley
 #
 #CFLAGS = -O -g
-CFLAGS = -O3
+#CFLAGS = -O3
 LINTFLAGS = -lc -lm
 SHELL = /bin/sh
 #CC = cc
diff '--color=auto' -ruN fasthenry-3.0wr.orig/src/zbuf/mk_syscfg.inc fasthenry-3.0wr/src/zbuf/mk_syscfg.inc
--- fasthenry-3.0wr.orig/src/zbuf/mk_syscfg.inc	2020-07-23 00:18:23.000000000 +0200
+++ fasthenry-3.0wr/src/zbuf/mk_syscfg.inc	2025-10-25 23:06:26.660231747 +0200
@@ -2,7 +2,7 @@
 # except for MinGW.
 
 #CFLAGS = -O -g -DFOUR
-CFLAGS = -O3 -DFOUR
+CFLAGS += -DFOUR
 
 # For MinGW, there is no getrusage, and we'll skip a gethostname call
 # to avoid having to link with winsock.
@@ -12,4 +12,4 @@
 
 # We're going to assume gcc, you'll need to comment this if a
 # non-compatible compiler is used.
-CC := gcc
+#CC := gcc