diff --git a/authprogs/Makefile b/authprogs/Makefile
index 87558a9f0..696f73d92 100644
--- a/authprogs/Makefile
+++ b/authprogs/Makefile
@@ -12,7 +12,7 @@ SOURCES       = auth_krb5.c ckpasswd.c domain.c ident.c libinnauth.c radius.c
 all: $(ALL)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	if [ x"$(KRB5_AUTH)" != x ] ; then \
diff --git a/backends/Makefile b/backends/Makefile
index ac71bea03..d4c3a9c99 100644
--- a/backends/Makefile
+++ b/backends/Makefile
@@ -18,7 +18,7 @@ SOURCES       = actsync.c archive.c batcher.c buffchan.c cvtbatch.c \
 all: $(ALL) $(MAN)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	for F in actmerge actsyncd news2mail nntpsend send-ihave \
diff --git a/contrib/Makefile b/contrib/Makefile
index b585a46f6..a406dbd92 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -18,7 +18,7 @@ ALL	      = analyze-traffic archivegz authmysql auth_pass backlogstat \
 all: $(ALL)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 clean clobber distclean maintclean:
 	rm -f *.o $(ALL)
diff --git a/control/Makefile b/control/Makefile
index 7c4092ea7..8371627b8 100644
--- a/control/Makefile
+++ b/control/Makefile
@@ -13,7 +13,7 @@ SOURCES	      = gencancel.c
 all: $(ALL) $(MAN)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_XPRI) gencancel $D$(PATHBIN)/gencancel
diff --git a/expire/Makefile b/expire/Makefile
index 8241b2889..dd70fdea4 100644
--- a/expire/Makefile
+++ b/expire/Makefile
@@ -12,7 +12,7 @@ SOURCES       = convdate.c expire.c expireover.c fastrm.c grephistory.c \
 all: $(ALL)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	for F in convdate fastrm grephistory ; do \
diff --git a/frontends/Makefile b/frontends/Makefile
index 093b33697..524b2e6e2 100644
--- a/frontends/Makefile
+++ b/frontends/Makefile
@@ -23,10 +23,10 @@ PATHRNEWS     = $(PATHBIN)/rnews.libexec
 all: $(ALL) $(MAN)
 
 optional:
-	$(MAKE) COPT='$(WARNINGS)' $(OPTIONAL)
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" $(OPTIONAL)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_INEWS) inews $D$(PATHBIN)/inews
diff --git a/history/Makefile b/history/Makefile
index 534ad037c..1e0cc9760 100644
--- a/history/Makefile
+++ b/history/Makefile
@@ -24,7 +24,7 @@ all: library programs
 include Make.methods
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_LPUB) libinnhist.$(EXTLIB) $D$(PATHLIB)/libinnhist.$(EXTLIB)
diff --git a/innd/Makefile b/innd/Makefile
index e77f8bd2c..9b2ac8da1 100644
--- a/innd/Makefile
+++ b/innd/Makefile
@@ -16,7 +16,7 @@ OBJECTS		= $(SOURCES:.c=.o)
 all: $(ALL)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_XPRI) innd $D$(PATHBIN)/innd
diff --git a/innfeed/Makefile b/innfeed/Makefile
index f3cccbf7c..669b37d38 100644
--- a/innfeed/Makefile
+++ b/innfeed/Makefile
@@ -20,7 +20,7 @@ OBJECTS	      = article.o buffer.o config_l.o config_y.o endpoint.o host.o \
 all: $(ALL)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_XPRI) innfeed $D$(PATHBIN)/innfeed
diff --git a/lib/Makefile b/lib/Makefile
index 12f3340b9..5f92d2a9d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -42,7 +42,7 @@ LOBJECTS      = $(OBJECTS:.o=.lo)
 all: libinn.$(EXTLIB) canlock.o perl.o
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_LPUB) libinn.$(EXTLIB) $D$(PATHLIB)/libinn.$(EXTLIB)
diff --git a/nnrpd/Makefile b/nnrpd/Makefile
index 47c9d4846..68667e643 100644
--- a/nnrpd/Makefile
+++ b/nnrpd/Makefile
@@ -17,7 +17,7 @@ OBJECTS		= $(SOURCES:.c=.o)
 all: $(ALL)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_XPUB) nnrpd $D$(PATHBIN)/nnrpd
diff --git a/storage/Makefile b/storage/Makefile
index b77ae6d08..6941a62d2 100644
--- a/storage/Makefile
+++ b/storage/Makefile
@@ -32,7 +32,7 @@ FIX	= $(SHELL) $(FIXSCRIPT)
 include Make.methods
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' all
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" all
 
 install: all
 	$(LI_LPUB) libinnstorage.$(EXTLIB) $D$(PATHLIB)/libinnstorage.$(EXTLIB)
diff --git a/tests/Makefile b/tests/Makefile
index 31d3be9d1..f20c15a57 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -42,7 +42,7 @@ all check test tests: $(TESTS) $(EXTRA)
 build: $(TESTS) $(EXTRA)
 
 warnings:
-	$(MAKE) COPT='$(WARNINGS)' build
+	$(MAKE) COPT="$(COPT) $(WARNINGS)" build
 
 clean clobber distclean maintclean:
 	rm -f *.o *.lo */*.o */*.lo */*/*.o */*/*.o \