diff --git a/cricket/Makefile b/cricket/Makefile
index fb1682b..1ccdeca 100644
--- a/cricket/Makefile
+++ b/cricket/Makefile
@@ -20,6 +20,8 @@ DD = $(shell date "+%-d")
 YY = $(shell date "+%-y")
 DEFINES = -D DD=$(DD) -D MM=$(MM) -D YY=$(YY)
 
+XATTR := $(shell command -v xattr 2> /dev/null)
+
 .PHONY: clean all
 all: $(OUTDIR) $(TARGETS)
 
@@ -36,4 +38,6 @@ $(OUTDIR)/%.o: %.s $(HEADERS)
 
 $(OUTDIR)/%.BIN $(OUTDIR)/%.SYS: $(OUTDIR)/%.o
 	ld65 $(LDFLAGS) -o $@ $<
-	if command -v xattr &> /dev/null; then xattr -wx prodos.AuxType '00 20' $@; fi
+ifdef XATTR
+	xattr -wx prodos.AuxType '00 20' $@
+endif
diff --git a/dclock/Makefile b/dclock/Makefile
index 9e1d279..057049b 100644
--- a/dclock/Makefile
+++ b/dclock/Makefile
@@ -15,6 +15,8 @@ DD = $(shell date "+%-d")
 YY = $(shell date "+%-y")
 DEFINES = -D DD=$(DD) -D MM=$(MM) -D YY=$(YY)
 
+XATTR := $(shell command -v xattr 2> /dev/null)
+
 .PHONY: clean all
 all: $(OUTDIR) $(TARGETS)
 
@@ -31,4 +33,6 @@ $(OUTDIR)/%.o: %.s $(HEADERS)
 
 $(OUTDIR)/%.SYS: $(OUTDIR)/%.o
 	ld65 $(LDFLAGS) -o $@ $<
-	if command -v xattr &> /dev/null; then xattr -wx prodos.AuxType '00 20' $@; fi
+ifdef XATTR
+	xattr -wx prodos.AuxType '00 20' $@
+endif
diff --git a/ns.clock/Makefile b/ns.clock/Makefile
index 9c754f6..c4a2210 100644
--- a/ns.clock/Makefile
+++ b/ns.clock/Makefile
@@ -15,6 +15,8 @@ DD = $(shell date "+%-d")
 YY = $(shell date "+%-y")
 DEFINES = -D DD=$(DD) -D MM=$(MM) -D YY=$(YY)
 
+XATTR := $(shell command -v xattr 2> /dev/null)
+
 .PHONY: clean all
 all: $(OUTDIR) $(TARGETS)
 
@@ -31,4 +33,6 @@ $(OUTDIR)/%.o: %.s $(HEADERS)
 
 $(OUTDIR)/%.SYS: $(OUTDIR)/%.o
 	ld65 $(LDFLAGS) -o $@ $<
-	if command -v xattr &> /dev/null; then xattr -wx prodos.AuxType '00 20' $@; fi
+ifdef XATTR
+	xattr -wx prodos.AuxType '00 20' $@
+endif
diff --git a/quit/Makefile b/quit/Makefile
index 081f47f..d1c4a1a 100644
--- a/quit/Makefile
+++ b/quit/Makefile
@@ -15,6 +15,8 @@ DD = $(shell date "+%-d")
 YY = $(shell date "+%-y")
 DEFINES = -D DD=$(DD) -D MM=$(MM) -D YY=$(YY)
 
+XATTR := $(shell command -v xattr 2> /dev/null)
+
 .PHONY: clean all
 all: $(OUTDIR) $(TARGETS)
 
@@ -31,4 +33,6 @@ $(OUTDIR)/%.o: %.s $(HEADERS)
 
 $(OUTDIR)/%.SYS: $(OUTDIR)/%.o
 	ld65 $(LDFLAGS) -o $@ $<
-	if command -v xattr &> /dev/null; then xattr -wx prodos.AuxType '00 20' $@; fi
+ifdef XATTR
+	xattr -wx prodos.AuxType '00 20' $@
+endif
diff --git a/ram.drv/Makefile b/ram.drv/Makefile
index 2eb3b48..b1e1a95 100644
--- a/ram.drv/Makefile
+++ b/ram.drv/Makefile
@@ -15,6 +15,8 @@ DD = $(shell date "+%-d")
 YY = $(shell date "+%-y")
 DEFINES = -D DD=$(DD) -D MM=$(MM) -D YY=$(YY)
 
+XATTR := $(shell command -v xattr 2> /dev/null)
+
 .PHONY: clean all
 all: $(OUTDIR) $(TARGETS)
 
@@ -31,4 +33,6 @@ $(OUTDIR)/%.o: %.s $(HEADERS)
 
 $(OUTDIR)/%.SYS: $(OUTDIR)/%.o
 	ld65 $(LDFLAGS) -o $@ $<
-	if command -v xattr &> /dev/null; then xattr -wx prodos.AuxType '00 20' $@; fi
+ifdef XATTR
+	xattr -wx prodos.AuxType '00 20' $@
+endif
diff --git a/selectors/Makefile b/selectors/Makefile
index 0bdad96..2acc526 100644
--- a/selectors/Makefile
+++ b/selectors/Makefile
@@ -18,6 +18,8 @@ DD = $(shell date "+%-d")
 YY = $(shell date "+%-y")
 DEFINES = -D DD=$(DD) -D MM=$(MM) -D YY=$(YY)
 
+XATTR := $(shell command -v xattr 2> /dev/null)
+
 .PHONY: clean all
 all: $(OUTDIR) $(TARGETS)
 
@@ -34,4 +36,6 @@ $(OUTDIR)/%.o: %.s $(HEADERS)
 
 $(OUTDIR)/%.SYS: $(OUTDIR)/%.o
 	ld65 $(LDFLAGS) -o $@ $<
-	if command -v xattr &> /dev/null; then xattr -wx prodos.AuxType '00 20' $@; fi
+ifdef XATTR
+	xattr -wx prodos.AuxType '00 20' $@
+endif