Allow to control test Makefile output via QUIET (like libsrc).

test/err/Makefile

@@ -5,16 +5,25 @@ ifneq ($(shell echo),)
 endif
 
 ifdef CMD_EXE
+  S = $(subst /,\,/)
   NOT = - # Hack
+  NULLDEV = nul:
   MKDIR = mkdir $(subst /,\,$1)
   RMDIR = -rmdir /s /q $(subst /,\,$1)
 else
+  S = /
   NOT = !
+  NULLDEV = /dev/null
   MKDIR = mkdir -p $1
   RMDIR = $(RM) -r $1
 endif
 
-CC65 := $(if $(wildcard ../../bin/cc65*),../../bin/cc65,cc65)
+ifdef QUIET
+  .SILENT:
+  NULLERR = 2>$(NULLDEV)
+endif
+
+CC65 := $(if $(wildcard ../../bin/cc65*),..$S..$Sbin$Scc65,cc65)
 
 WORKDIR = ../../testwrk/err
 
@@ -26,7 +35,8 @@ TESTS = $(patsubst %.c,$(WORKDIR)/%.s,$(SOURCES))
 all: $(TESTS)
 
 $(WORKDIR)/%.s: %.c
-	$(NOT) $(CC65) -o $@ $<
+	$(if $(QUIET),echo err/$*.s)
+	$(NOT) $(CC65) -o $@ $< $(NULLERR)
 
 clean:
 	@$(call RMDIR,$(WORKDIR))