diff --git a/src/devices/bus/isa/isa.h b/src/devices/bus/isa/isa.h
index d1f45c81d98..901a1634509 100644
--- a/src/devices/bus/isa/isa.h
+++ b/src/devices/bus/isa/isa.h
@@ -186,10 +186,13 @@ class isa8_device : public device_t,
 					public device_memory_interface
 {
 public:
-	static constexpr int AS_ISA_MEM    = 0;
-	static constexpr int AS_ISA_IO     = 1;
-	static constexpr int AS_ISA_MEMALT = 2;
-	static constexpr int AS_ISA_IOALT  = 3;
+	enum
+	{
+		AS_ISA_MEM    = 0,
+		AS_ISA_IO     = 1,
+		AS_ISA_MEMALT = 2,
+		AS_ISA_IOALT  = 3
+	};
 
 	// construction/destruction
 	isa8_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
diff --git a/src/devices/machine/gt64xxx.h b/src/devices/machine/gt64xxx.h
index 3b713985530..49daa47c35c 100644
--- a/src/devices/machine/gt64xxx.h
+++ b/src/devices/machine/gt64xxx.h
@@ -113,8 +113,11 @@ protected:
 
 
 private:
-	static constexpr int AS_PCI_MEM = 1;
-	static constexpr int AS_PCI_IO = 2;
+	enum
+	{
+		AS_PCI_MEM = 1,
+		AS_PCI_IO = 2
+	};
 
 	struct galileo_timer
 	{
diff --git a/src/devices/machine/pci.h b/src/devices/machine/pci.h
index c8a28a72050..53a171cbb21 100644
--- a/src/devices/machine/pci.h
+++ b/src/devices/machine/pci.h
@@ -200,7 +200,10 @@ public:
 	DECLARE_WRITE16_MEMBER(bridge_control_w);
 
 protected:
-	static constexpr int AS_PCI_CONFIG = 0;
+	enum
+	{
+		AS_PCI_CONFIG = 0
+	};
 
 	pci_bridge_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock);
 
diff --git a/src/devices/machine/vrc4373.h b/src/devices/machine/vrc4373.h
index 176aed79e0c..5e14ee335a1 100644
--- a/src/devices/machine/vrc4373.h
+++ b/src/devices/machine/vrc4373.h
@@ -70,8 +70,11 @@ protected:
 	address_space *m_cpu_space;
 
 private:
-	static constexpr int AS_PCI_MEM = 1;
-	static constexpr int AS_PCI_IO = 2;
+	enum
+	{
+		AS_PCI_MEM = 1,
+		AS_PCI_IO = 2
+	};
 
 	DECLARE_ADDRESS_MAP(cpu_map, 32);
 
diff --git a/src/devices/machine/vrc5074.h b/src/devices/machine/vrc5074.h
index 375a02677b5..dcb1487de00 100644
--- a/src/devices/machine/vrc5074.h
+++ b/src/devices/machine/vrc5074.h
@@ -72,8 +72,11 @@ protected:
 	virtual void device_reset() override;
 
 private:
-	static constexpr int AS_PCI_MEM = 1;
-	static constexpr int AS_PCI_IO = 2;
+	enum
+	{
+		AS_PCI_MEM = 1,
+		AS_PCI_IO = 2
+	};
 
 	mips3_device *m_cpu;
 	const char *cpu_tag;