Add a PT_NOTE section to mark build_id.

nacl/dyn-link/ldscripts/elf_nacl.x.static

 /* Linker script for glibc static linking.
    Usage: path_to_sdk/bin/nacl-gcc [usual options] -static
               -T path-to-toolchain/x86_64-nacl/lib/ldscripts/elf_nacl.x.static
 
    TODO(mseaborn): Make this work with "-static" on its own.
    See http://code.google.com/p/nativeclient/issues/detail?id=1198
 */
 OUTPUT_FORMAT("elf32-nacl", "elf32-nacl",
               "elf32-nacl")
 OUTPUT_ARCH(i386)
 ENTRY(_start)
 SEARCH_DIR("=/usr/local/lib32"); SEARCH_DIR("=/lib32"); SEARCH_DIR("=/usr/lib32");
 SEARCH_DIR("=/usr/local/lib"); SEARCH_DIR("=/lib"); SEARCH_DIR("=/usr/lib");
 PHDRS
 {
   headers PT_PHDR FILEHDR PHDRS ;  /* put the headers in a non-loadable seg */
-  seg_code    PT_LOAD FLAGS(5) ;   /* read + execute */
-  seg_rodata  PT_LOAD FLAGS(4) ;   /* read */
-  seg_tls     PT_TLS  FLAGS(4) ;
-  seg_rwdata  PT_LOAD FLAGS(6) ;   /* read + write */
+  seg_code     PT_LOAD FLAGS(5) ;   /* read + execute */
+  seg_rodata   PT_LOAD FLAGS(4) ;   /* read */
+  seg_tls      PT_TLS  FLAGS(4) ;
+  seg_rwdata   PT_LOAD FLAGS(6) ;   /* read + write */
+  seg_build_id PT_NOTE FLAGS(4) ;
 }
 SECTIONS
 {
   /* Read-only sections, merged into text segment: */
   PROVIDE (__executable_start = 0x20000); . = 0x20000;
   .plt            : { *(.plt) }
   /* I couldn't get ld to add NOP-padding between output sections
      (only between input sections within an output section),
      so I have simply combined .init and .text */
   .text           : SUBALIGN(32)
@@ skipping 13 matching lines @@
   PROVIDE (_etext = .);
   PROVIDE (etext = .);
 
   . = DEFINED(__nacl_rodata_start) ? __nacl_rodata_start : .;
   . = ALIGN(CONSTANT (MAXPAGESIZE)); /* nacl wants page alignment */
   .note.gnu.build-id :
   {
     PROVIDE_HIDDEN (__note_gnu_build_id_start = .);
     *(.note.gnu.build-id)
     PROVIDE_HIDDEN (__note_gnu_build_id_end = .);
-  } :seg_rodata
-  .hash           : { *(.hash) }
+  } :seg_rodata :seg_build_id
+  .hash           : { *(.hash) } :seg_rodata
   .gnu.hash       : { *(.gnu.hash) }
   .dynsym         : { *(.dynsym) }
   .dynstr         : { *(.dynstr) }
   .gnu.version    : { *(.gnu.version) }
   .gnu.version_d  : { *(.gnu.version_d) }
   .gnu.version_r  : { *(.gnu.version_r) }
   .rel.init       : { *(.rel.init) }
   .rel.text       : { *(.rel.text .rel.text.* .rel.gnu.linkonce.t.*) }
   .rel.fini       : { *(.rel.fini) }
   .rel.rodata     : { *(.rel.rodata .rel.rodata.* .rel.gnu.linkonce.r.*) }
@@ skipping 138 matching lines @@
   .debug_funcnames 0 : { *(.debug_funcnames) }
   .debug_typenames 0 : { *(.debug_typenames) }
   .debug_varnames  0 : { *(.debug_varnames) }
   /* DWARF 3 */
   .debug_pubtypes 0 : { *(.debug_pubtypes) }
   .debug_ranges   0 : { *(.debug_ranges) }
   .gnu.attributes 0 : { KEEP (*(.gnu.attributes)) }
   /DISCARD/ : { *(.note.GNU-stack) *(.gnu_debuglink) }
   /DISCARD/ : { *(.note.ABI-tag) }
 }