add .text.startup section

tests/test_c/tb.ld

@@ -1,5 +1,4 @@
 OUTPUT_ARCH( "riscv" )
-ENTRY(_start)
 
 MEMORY
 {
@@ -14,6 +13,7 @@ SECTIONS
     {
         /* . = ALIGN(4); */
         _text = .;
+        *(.text.startup)
         *(.text*)
         *(.rodata*)
         _etext = .;