diff --git a/include/pemagine/pe_api.h b/include/pemagine/pe_api.h
index 8a1e9f8..e192484 100644
--- a/include/pemagine/pe_api.h
+++ b/include/pemagine/pe_api.h
@@ -2,7 +2,7 @@
 #define PE_API_H
 
 /* portable integer types */
-#if defined (MIDIPIX_FREESTANDING)
+#if defined (_MIDIPIX_FREESTANDING)
 #include <psxtypes/psxtypes.h>
 #else
 #include <stdint.h>
diff --git a/project/extras.mk b/project/extras.mk
index 5f008e4..f9ddb03 100644
--- a/project/extras.mk
+++ b/project/extras.mk
@@ -1,7 +1,7 @@
 CFLAGS_SHARED_ATTR 	+= -DPE_EXPORT
 CFLAGS_STATIC_ATTR 	+= -DPE_STATIC
 
-CFLAGS_CONFIG 		+= -DMIDIPIX_FREESTANDING -D__NT$(HOST_BITS)
+CFLAGS_CONFIG 		+= -D_MIDIPIX_FREESTANDING -D__NT$(HOST_BITS)
 CFLAGS_CONFIG 		+= -UWIN32 -U_WIN32 -U__WIN32 -U__WIN32__
 CFLAGS_CONFIG 		+= -UWIN64 -U_WIN64 -U__WIN64 -U__WIN64__