diff --git a/Makefile b/Makefile
index 9c0a336..088606c 100644
--- a/Makefile
+++ b/Makefile
@@ -844,7 +844,7 @@
 
 USE_X86_PORT_IO := $(if $(call filter_deps,$(DEPENDS_ON_X86_PORT_IO)),yes,no)
 ifeq ($(USE_X86_PORT_IO), yes)
-FEATURE_FLAGS += -D'__FLASHPROG_HAVE_OUTB__=1'
+FEATURE_FLAGS += -D'HAVE_OUTB=1'
 PROGRAMMER_OBJS += hwaccess_x86_io.o
 endif
 
diff --git a/meson.build b/meson.build
index 50412a9..f9f860c 100644
--- a/meson.build
+++ b/meson.build
@@ -134,6 +134,7 @@
 if systems_hwaccess.contains(host_machine.system())
   srcs += files('hwaccess_physmap.c')
   if ['x86', 'x86_64'].contains(host_machine.cpu_family())
+    add_project_arguments('-DHAVE_OUTB=1', language : 'c')
     srcs += files('hwaccess_x86_msr.c', 'hwaccess_x86_io.c')
   endif
 endif
diff --git a/pcidev.c b/pcidev.c
index e2dceb4..57bd20b 100644
--- a/pcidev.c
+++ b/pcidev.c
@@ -121,7 +121,7 @@
 		break;
 	case TYPE_IOBAR:
 		msg_pdbg("I/O\n");
-#if __FLASHPROG_HAVE_OUTB__
+#if HAVE_OUTB
 		if (!(supported_cycles & PCI_COMMAND_IO)) {
 			msg_perr("I/O BAR access requested, but device has I/O space accesses disabled.\n");
 			/* TODO: Abort here? */