diff --git a/configure.ac b/configure.ac
index 91d651e..b36f7f6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -448,7 +448,7 @@ if test x$use_extern_gtg = xyes; then
         GTG_LDFLAGS="${LDFLAGS} -L$gtgdir/lib/ -lgtg"
 	CHECK_LIB_LDFLAGS([gtg], [setTraceType],"$GTG_LDFLAGS", , AC_MSG_ERROR([cannot find libgtg]))
 	CHECK_LIB_LDFLAGS([gtg], [gtg_record],"$GTG_LDFLAGS", GTG_OUT_OF_ORDER=1, GTG_OUT_OF_ORDER=0)
-	CHECK_HEADER_CPPFLAGS([GTGBasic1.h],, "$GTG_CPPFLAGS", AC_MSG_ERROR([cannot find headers for gtg]))
+	CHECK_HEADER_CPPFLAGS([GTGBasic.h],, "$GTG_CPPFLAGS", AC_MSG_ERROR([cannot find headers for gtg]))
 else
 
     GTG_OUT_OF_ORDER=1
