diff --git a/configs/haiku b/configs/haiku
index c5ed38f257..223f7cac2a 100644
--- a/configs/haiku
+++ b/configs/haiku
@@ -15,7 +15,8 @@ DEFINES = \
 	-DUSE_X86_ASM \
 	-DUSE_MMX_ASM \
 	-DUSE_3DNOW_ASM \
-	-DUSE_SSE_ASM
+	-DUSE_SSE_ASM \
+	-DPTHREADS
 #	-DBEOS_THREADS
  
 MESA_ASM_SOURCES = $(X86_SOURCES)