lowfat: get rid of absolute relocation that prevents PIC

Author: ddcc

llvm-4.0.0.src/projects/compiler-rt/lib/lowfat/lowfat.c

@@ -579,8 +579,7 @@ __asm__ (
     "\t.type lowfat_stack_pivot,@function\n"
     "lowfat_stack_pivot:\n"
     "\tmovq %rsp, %rdi\n"
-    "\tmovabsq $lowfat_stack_pivot_2, %rax\n"
-    "\tcallq *%rax\n"
+    "\tcall lowfat_stack_pivot_2\n"
     "\tmovq %rax, %rsp\n"
     "\tretq\n"
 );