Add llvm-readobj and binutils symlinks to LLVM_TOOLCHAIN_TOOLS

This patch adds llvm-readobj and the binutils symlink for readelf to
LLVM_TOOLCHAIN_TOOLS.

Tvoid *thread, void *attr,hey are required by some (most?)
autoconf-built libraries, adding these allows me to build newlib with
the toolchain generated this way.

Also opened an issue for that some days ago, see
https://bugs.llvm.org/show_bug.cgi?id=50698

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D104957

Author: LittleFox94

llvm/cmake/modules/AddLLVM.cmake

@@ -1199,6 +1199,7 @@ if(NOT LLVM_TOOLCHAIN_TOOLS)
     llvm-objcopy
     llvm-objdump
     llvm-rc
+    llvm-readobj
     llvm-size
     llvm-strings
     llvm-strip
@@ -1213,6 +1214,7 @@ if(NOT LLVM_TOOLCHAIN_TOOLS)
     nm
     objcopy
     objdump
+    readelf
     size
     strings
     strip