diff --git a/lib/include/picrin/setup.h b/lib/include/picrin/setup.h
index a714862d..5e0ff189 100644
--- a/lib/include/picrin/setup.h
+++ b/lib/include/picrin/setup.h
@@ -480,6 +480,7 @@ double PIC_CSTRING_TO_DOUBLE(const char *);
 #endif
 
 #if __x86_64__ && (defined(__GNUC__) || defined(__clang__)) && ! defined(__STRICT_ANSI__)
+# include <stdint.h>
 # define PIC_NAN_BOXING 1
 #else
 # define PIC_NAN_BOXING 0
diff --git a/tools/mkboot.scm b/tools/mkboot.scm
index 28ad84f0..dc4a6a9a 100644
--- a/tools/mkboot.scm
+++ b/tools/mkboot.scm
@@ -1,4 +1,6 @@
-(import (picrin base))
+(import (scheme base)
+        (scheme read)
+        (scheme write))
 
 (define (with-output-to-string thunk)
   (let ((port (open-output-string)))