diff --git a/Makefile b/Makefile
index 45eaf70dd..dacc0d2bc 100644
--- a/Makefile
+++ b/Makefile
@@ -31,6 +31,7 @@ OS:=beos
 else
 OS:=linux
 endif
+endif
 
 windows_SO_TYPE:=dll
 osx_SO_TYPE:=bundle
@@ -158,9 +159,13 @@ ARCH_LIBS:=obj/postscript_print.o
 
 # The entire set of CFLAGS:
 
+# FIXME: src/test-option.sh runs every time
+# FIXME: -Wstrict-aliasing=2 not used
+
 #-ffast-math
 OPTFLAGS:=-O2
 CFLAGS:=$(OPTFLAGS) -W -Wall -fno-common -ffloat-store \
+	-fvisibility=hidden \
 	-Wcast-align -Wredundant-decls \
 	-Wbad-function-cast -Wwrite-strings \
 	-Waggregate-return \
diff --git a/magic/Makefile b/magic/Makefile
index 06e82c920..78bb811f9 100644
--- a/magic/Makefile
+++ b/magic/Makefile
@@ -19,7 +19,7 @@ SO_TYPE:=so
 TP_MAGIC_CFLAGS:=$(shell if [ -x tp-magic-config ] ; then tp-magic-config --cflags ; else echo -I../src/ ; fi)
 
 SDL_CFLAGS:=$(shell sdl-config --cflags)
-CFLAGS:=-g3 -O2 -W -Wstrict-prototypes -Wmissing-prototypes -Wall $(SDL_CFLAGS) $(TP_MAGIC_CFLAGS)
+CFLAGS:=-g3 -O2 -fvisibility=hidden -fno-common -W -Wstrict-prototypes -Wmissing-prototypes -Wall $(SDL_CFLAGS) $(TP_MAGIC_CFLAGS)
 SHARED_FLAGS:=-shared -fpic
 
 SDL_MIXER_LIB:=-lSDL_mixer