Allow the _ prefix of macOS

Author: dspinellis

src/Makefile

@@ -85,7 +85,7 @@ verify-global-defs: # Help: Verify prefix of globally visible definitions
 	$(CC) $(CFLAGS) $(RL_SRC) -c
 	# Check that global not undefined (U) definitions are prefixed
 	# The output (grep success) signifies unprefixed global defs
-	! nm *.o | sed 's/^ /x/' | awk '$$2 ~ /[A-TVZ]/ {print $$3}' | grep -Ev '^(acl|ini|curl)'
+	! nm *.o | sed 's/^ /x/' | awk '$$2 ~ /[A-TVZ]/ {print $$3}' | grep -Ev '^_?(acl|ini|curl)'
 
 e2e-run: $(PROGS) # Help: Invoke the library with a readline read/print loop
 	$(PRELOAD_VAR)=`pwd`/$(SHARED_LIB) $(SET_ADD_LIB) ./rl_driver