Enforce a minimum architecture for ARM.

This was added in 558ee7 to master.

Makefile

@@ -147,6 +147,23 @@ endif
 
 # ----------
 
+# ARM needs a sane minimum architecture. We need the `yield`
+# opcode, arm6k is the first iteration that supports it. arm6k
+# is also the first Raspberry PI generation and older hardware
+# is likely too slow to run the game. We're not enforcing the
+# minimum architecture, but if you're build for something older
+# like arm5 you need to remove the `yield` opcode. It's set in
+# Qcommon_Mainloop() in frame.c via inline assmebly.
+ifeq ($(YQ2_ARCH), arm)
+CFLAGS += -march=armv6k
+endif
+
+ifeq ($(YQ2_ARCH), aarch64)
+CFLAGS += -march=armv8.0-a
+endif
+
+# ----------
+
 # Switch of some annoying warnings.
 ifeq ($(COMPILER), clang)
 	# -Wno-missing-braces because otherwise clang complains
@@ -191,16 +208,6 @@ ifeq ($(YQ2_ARCH), x86_64)
 override CFLAGS += -mfpmath=sse
 endif
 
-# In ARM mode it cannot generate yield instruction
-# to cool down the CPU in busy mode
-ifeq ($(YQ2_ARCH), arm)
-CFLAGS += -march=armv6k
-endif
-
-ifeq ($(YQ2_ARCH), aarch64)
-CFLAGS += -march=armv8-a
-endif
-
 # ----------
 
 # Systemwide installation.