diff --git a/Makefile b/Makefile
index 0da12d60bd..25393970bc 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ COBJ   = $(CSRC:.c=.o)
 LUAJIT_O := deps/luajit/src/libluajit.a
 SYSCALL  := src/syscall.lua
 
-LUAJIT_CFLAGS := -DLUAJIT_USE_PERFTOOLS -DLUAJIT_USE_GDBJIT -DLUAJIT_NUMMODE=3
+LUAJIT_CFLAGS := -DLUAJIT_USE_PERFTOOLS -DLUAJIT_USE_GDBJIT -DLUAJIT_NUMMODE=3 -include $(CURDIR)/gcc-preinclude.h
 
 all: $(LUAJIT_O) $(SYSCALL)
 	cd src && $(MAKE)
diff --git a/gcc-preinclude.h b/gcc-preinclude.h
new file mode 100644
index 0000000000..99b4e0cc87
--- /dev/null
+++ b/gcc-preinclude.h
@@ -0,0 +1,8 @@
+// Force an old symbol version on memcpy.
+// See: http://www.win.tue.nl/~aeb/linux/misc/gcc-semibug.html
+//      https://rjpower9000.wordpress.com/2012/04/09/fun-with-shared-libraries-version-glibc_2-14-not-found/
+
+#ifndef __ASSEMBLER__
+__asm__(".symver memcpy,memcpy@GLIBC_2.2.5");
+#endif
+
diff --git a/src/Makefile b/src/Makefile
index a375383f0c..87d2775236 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -45,7 +45,7 @@ snabb: $(LUAOBJ) $(HOBJ) $(COBJ) $(ASMOBJ)
 	$(E) "LINK      $@"
 	$(Q) gcc -Wl,--no-as-needed -Wl,-E -Werror -Wall -o $@ $^ \
 	    ../deps/luajit/src/libluajit.a \
-	    -lc -ldl -lm -lrt -lpthread
+	    -lrt -lc -ldl -lm -lpthread
 	@echo -n "Firmware: "
 	@ln -fs snabb snabbswitch
 	@ls -sh snabb
@@ -99,7 +99,7 @@ $(LUAOBJ): obj/%_lua.o: %.lua Makefile | $(OBJDIR)
 
 $(COBJ): obj/%_c.o: %.c $(CHDR) Makefile | $(OBJDIR)
 	$(E) "C         $@"
-	$(Q) gcc -Wl,-E -I ../deps/luajit/src -I . -c -Wall -Werror -o $@ $<
+	$(Q) gcc -Wl,-E -I ../deps/luajit/src -I . -include $(CURDIR)/../gcc-preinclude.h -c -Wall -Werror -o $@ $<
 
 $(HOBJ): obj/%_h.o: %.h Makefile | $(OBJDIR)
 	$(E) "H         $@"
diff --git a/src/selftest.sh b/src/selftest.sh
new file mode 100755
index 0000000000..764ab1e63f
--- /dev/null
+++ b/src/selftest.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+echo "selftest: ./snabb binary portability"
+echo "Scanning for symbols requiring GLIBC > 2.7"
+if objdump -T snabb | \
+   awk '/GLIBC/ { print $(NF-1), $NF }' | \
+   grep -v 'GLIBC_2\.[0-7][\. ]'; then
+    echo "^^^ Error ^^^" >&2
+    echo "(You might just need to 'make clean; make' at the top level.)"
+    exit 1
+fi
+echo "selftest: ok"