diff --git a/config.mk b/config.mk
index 1dac29b..c225df1 100644
--- a/config.mk
+++ b/config.mk
@@ -44,22 +44,6 @@
 PLATFORM_CPPFLAGS =
 PLATFORM_LDFLAGS =
 
-#
-# When cross-compiling on NetBSD, we have to define __PPC__ or else we
-# will pick up a va_list declaration that is incompatible with the
-# actual argument lists emitted by the compiler.
-#
-# [Tested on NetBSD/i386 1.5 + cross-powerpc-netbsd-1.3]
-
-ifeq ($(ARCH),ppc)
-ifeq ($(CROSS_COMPILE),powerpc-netbsd-)
-PLATFORM_CPPFLAGS+= -D__PPC__
-endif
-ifeq ($(CROSS_COMPILE),powerpc-openbsd-)
-PLATFORM_CPPFLAGS+= -D__PPC__
-endif
-endif
-
 ifeq ($(ARCH),arm)
 ifeq ($(CROSS_COMPILE),powerpc-netbsd-)
 PLATFORM_CPPFLAGS+= -D__ARM__
diff --git a/ppc_config.mk b/ppc_config.mk
index 31993bd..c95b3b1 100644
--- a/ppc_config.mk
+++ b/ppc_config.mk
@@ -23,3 +23,17 @@
 
 PLATFORM_CPPFLAGS += -DCONFIG_PPC -D__powerpc__
 PLATFORM_LDFLAGS  += -n
+
+#
+# When cross-compiling on NetBSD, we have to define __PPC__ or else we
+# will pick up a va_list declaration that is incompatible with the
+# actual argument lists emitted by the compiler.
+#
+# [Tested on NetBSD/i386 1.5 + cross-powerpc-netbsd-1.3]
+
+ifeq ($(CROSS_COMPILE),powerpc-netbsd-)
+PLATFORM_CPPFLAGS+= -D__PPC__
+endif
+ifeq ($(CROSS_COMPILE),powerpc-openbsd-)
+PLATFORM_CPPFLAGS+= -D__PPC__
+endif