1 files changed, 3 insertions, 1 deletions
diff --git a/built_in.h b/built_in.h
index a3b7bf8..8dd1824 100644
--- a/built_in.h
+++ b/built_in.h
@@ -178,7 +178,9 @@ typedef uint8_t		u8;
 # define bug()			assert(0)
 #endif
 
-#define PAGE_SIZE		(getpagesize())
+#ifndef PAGE_SIZE
+# define PAGE_SIZE		(getpagesize())
+#endif
 #define PAGE_MASK		(~(PAGE_SIZE - 1))
 #define PAGE_ALIGN(addr)	(((addr) + PAGE_SIZE - 1) & PAGE_MASK)