diff --git a/libblock/Makefile b/libblock/Makefile
index 0eda5cf..c568b6d 100644
--- a/libblock/Makefile
+++ b/libblock/Makefile
@@ -5,7 +5,7 @@
 TOP=$(shell pwd)
 
 68000FLAGS = -m68000 -Wa,-m68000
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
 CPPFLAGS = -I$(TOP)/../libmacos -DARCH_M68K -I$(TOP)/../libstream
 
 LIBRARY = libblock.a
diff --git a/libfloppy/Makefile b/libfloppy/Makefile
index f180020..66039a0 100644
--- a/libfloppy/Makefile
+++ b/libfloppy/Makefile
@@ -5,7 +5,7 @@
 TOP=$(shell pwd)
 
 68000FLAGS = -m68000 -Wa,-m68000
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
 CPPFLAGS = -I$(TOP)/../libmacos -DARCH_M68K
 
 LIBRARY = libfloppy.a
diff --git a/libgzip/Makefile b/libgzip/Makefile
index 1a24176..598a7d2 100644
--- a/libgzip/Makefile
+++ b/libgzip/Makefile
@@ -13,7 +13,7 @@ CC=$(CROSS_COMPILE)gcc
 LD=$(CROSS_COMPILE)ld
 AR=$(CROSS_COMPILE)ar
 
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar
 ifeq ($(TARGET), m68k-linux)
 68000FLAGS = -m68000 -Wa,-m68000
 CFLAGS += -fpic -O2 -Os
diff --git a/libiso9660/Makefile b/libiso9660/Makefile
index 936204e..d8a6b4a 100644
--- a/libiso9660/Makefile
+++ b/libiso9660/Makefile
@@ -11,7 +11,7 @@ LD=$(CROSS_COMPILE)ld
 AR=$(CROSS_COMPILE)ar
 
 TARGET = native
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar
 ifeq ($(TARGET), m68k-linux)
 68000FLAGS = -m68000 -Wa,-m68000
 CFLAGS += -fpic -O2 -Os
diff --git a/libmacos/Makefile b/libmacos/Makefile
index 39c2d93..3c4bd0c 100644
--- a/libmacos/Makefile
+++ b/libmacos/Makefile
@@ -5,7 +5,7 @@
 TOP	= $(shell pwd)
 
 68000FLAGS = -m68000 -Wa,-m68000
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
 CPPFLAGS	= -I$(TOP) -DARCH_M68K
 
 LIBRARY = libmacos.a
diff --git a/libscsi/Makefile b/libscsi/Makefile
index 93d44b6..d565feb 100644
--- a/libscsi/Makefile
+++ b/libscsi/Makefile
@@ -4,7 +4,7 @@
 
 TOP=$(shell pwd)
 68000FLAGS = -m68000 -Wa,-m68000
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
 CPPFLAGS = -I$(TOP)/../libmacos -DARCH_M68K
 
 LIBRARY = libscsi.a
diff --git a/libstream/Makefile b/libstream/Makefile
index d672c20..63cd7d4 100644
--- a/libstream/Makefile
+++ b/libstream/Makefile
@@ -5,7 +5,7 @@
 TOP = $(shell pwd)
 VPATH=$(TOP)
 
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -g -O2 -Os
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -g -O2 -Os
 #-m68000 -Wa,-m68000
 CPPFLAGS = -I$(TOP)/../libmacos -I$(TOP) -I$(TOP)/../libgzip
 
diff --git a/libunix/Makefile b/libunix/Makefile
index 155fdbe..b5a8ae5 100644
--- a/libunix/Makefile
+++ b/libunix/Makefile
@@ -5,7 +5,7 @@
 TOP = $(shell pwd)
 
 68000FLAGS = -m68000 -Wa,-m68000
-CFLAGS	= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
+CFLAGS	+= -nostdlib -nodefaultlibs -Wall -Werror -Wno-multichar -fpic -O2 -Os
 CPPFLAGS = -I$(TOP) -I$(TOP)/../libmacos -DARCH_M68K
 
 LIBRARY = libunix.a