Subzero: Support non-IRT immediate calls with -filetype=iasm.

pydir/szbuild.py

 #!/usr/bin/env python2
 
 import argparse
 import os
 import pipes
 import re
 import sys
 
 from utils import shellcmd
 from utils import FindBaseNaCl
@@ skipping 279 matching lines @@
                    'x86-32/lib').format(root=nacl_root)
         shellcmd((
             '{gold} -nostdlib --no-fix-cortex-a8 --eh-frame-hdr -z text ' +
             '--build-id --entry=__pnacl_start -static ' +
             '{linklib}/crtbegin.o {partial} ' +
             '{root}/toolchain_build/src/subzero/build/runtime/' +
             'szrt_sb_x8632.o ' +
             '{linklib}/libpnacl_irt_shim_dummy.a --start-group ' +
             '{linklib}/libgcc.a {linklib}/libcrt_platform.a ' +
             '--end-group {linklib}/crtend.o --undefined=_start ' +
+            '--defsym=__Sz_AbsoluteZero=0 ' +
             '-o {exe}'
             ).format(gold=gold, linklib=linklib, partial=obj_partial, exe=exe,
                      root=nacl_root),
                  echo=args.verbose)
     else:
         shellcmd((
             '{ld} -m32 {partial} -o {exe} ' +
             # Keep the rest of this command line (except szrt_native_x8632.o) in
             # sync with RunHostLD() in pnacl-translate.py.
             '{root}/toolchain/linux_x86/pnacl_newlib/translator/x86-32-linux/' +
             'lib/{{unsandboxed_irt,irt_random,irt_query_list}}.o ' +
             '{root}/toolchain_build/src/subzero/build/runtime/' +
-            'szrt_native_x8632.o -lpthread -lrt'
+            'szrt_native_x8632.o -lpthread -lrt ' +
+            '-Wl,--defsym=__Sz_AbsoluteZero=0'
             ).format(ld=linker, partial=obj_partial, exe=exe, root=nacl_root),
                  echo=args.verbose)
 
     # Put the extra verbose printing at the end.
     if args.verbose:
         print 'PATH: {path}'.format(path=path_addition)
         if hybrid:
             print 'include={regex}'.format(regex=re_include_str)
             print 'exclude={regex}'.format(regex=re_exclude_str)
             print 'default_match={dm}'.format(dm=default_match)
             print 'Number of Subzero syms = {num}'.format(num=len(sz_syms))
 
 if __name__ == '__main__':
     main()