diff --git a/Changelog.txt b/Changelog.txt
index ab8fb19c2..f4f9c6e35 100644
--- a/Changelog.txt
+++ b/Changelog.txt
@@ -3,7 +3,8 @@ OpenBLAS ChangeLog
 Version 0.1 alpha2(in development)
 
 common:
-	* 
+	* Fixed blasint undefined bug in <cblas.h> file. Other software 
+	  could include this header successfully(Refs issue #13 on github)
 x86/x86_64:
 	* 
 MIPS64:
diff --git a/Makefile.system b/Makefile.system
index 5a129732f..6fb0ec86f 100644
--- a/Makefile.system
+++ b/Makefile.system
@@ -30,6 +30,10 @@ ifdef TARGET
 GETARCH_FLAGS += -DFORCE_$(TARGET)
 endif
 
+ifdef INTERFACE64
+GETARCH_FLAGS	+= -DUSE64BITINT
+endif
+
 # This operation is expensive, so execution should be once.
 ifndef GOTOBLAS_MAKEFILE
 export GOTOBLAS_MAKEFILE = 1
@@ -489,7 +493,8 @@ endif
 
 ifdef BINARY64
 ifdef INTERFACE64
-CCOMMON_OPT	+= -DUSE64BITINT
+CCOMMON_OPT	+= 
+#-DUSE64BITINT
 endif
 endif
 
diff --git a/cblas.h b/cblas.h
index ea0fbb629..4beae7ad5 100644
--- a/cblas.h
+++ b/cblas.h
@@ -1,6 +1,9 @@
 #ifndef CBLAS_H
 #define CBLAS_H
 
+#include <stddef.h>
+#include "common.h"
+
 #define CBLAS_INDEX size_t
 
 enum CBLAS_ORDER     {CblasRowMajor=101, CblasColMajor=102};
diff --git a/getarch_2nd.c b/getarch_2nd.c
index 31babd28a..018f08d31 100644
--- a/getarch_2nd.c
+++ b/getarch_2nd.c
@@ -30,6 +30,10 @@ int main(int argc, char **argv) {
     printf("#define DLOCAL_BUFFER_SIZE\t%ld\n", (DGEMM_DEFAULT_Q * DGEMM_DEFAULT_UNROLL_N * 2 * 1 *  sizeof(double)));
     printf("#define CLOCAL_BUFFER_SIZE\t%ld\n", (CGEMM_DEFAULT_Q * CGEMM_DEFAULT_UNROLL_N * 4 * 2 *  sizeof(float)));
     printf("#define ZLOCAL_BUFFER_SIZE\t%ld\n", (ZGEMM_DEFAULT_Q * ZGEMM_DEFAULT_UNROLL_N * 2 * 2 *  sizeof(double)));
+
+#ifdef USE64BITINT
+	printf("#define USE64BITINT\n");
+#endif
   }
 
   return 0;