lto/addAsmGlobalSymbols: fail fracefully when the target does not define AsmParser.

autoconf/configure.ac

Index: autoconf/configure.ac
===================================================================
--- autoconf/configure.ac	(revision 139317)
+++ autoconf/configure.ac	(working copy)
@@ -603,13 +603,13 @@
 AC_ARG_ENABLE([targets],AS_HELP_STRING([--enable-targets],
     [Build specific host targets: all or target1,target2,... Valid targets are:
      host, x86, x86_64, sparc, powerpc, alpha, arm, mips, spu,
-     xcore, msp430, systemz, blackfin, ptx, cbe, and cpp (default=all)]),,
+     xcore, msp430, systemz, blackfin, ptx, pnacl, cbe, and cpp (default=all)]),,
     enableval=all)
 if test "$enableval" = host-only ; then
   enableval=host
 fi
 case "$enableval" in
-  all) TARGETS_TO_BUILD="X86 Sparc PowerPC Alpha ARM Mips CellSPU XCore MSP430 SystemZ Blackfin CBackend CppBackend MBlaze PTX" ;;
+  all) TARGETS_TO_BUILD="X86 Sparc PowerPC Alpha ARM Mips CellSPU XCore MSP430 SystemZ Blackfin CBackend CppBackend MBlaze PTX PNaCl" ;;
   *)for a_target in `echo $enableval|sed -e 's/,/ /g' ` ; do
       case "$a_target" in
         x86)      TARGETS_TO_BUILD="X86 $TARGETS_TO_BUILD" ;;
@@ -628,6 +628,7 @@
         cpp)      TARGETS_TO_BUILD="CppBackend $TARGETS_TO_BUILD" ;;
         mblaze)   TARGETS_TO_BUILD="MBlaze $TARGETS_TO_BUILD" ;;
         ptx)      TARGETS_TO_BUILD="PTX $TARGETS_TO_BUILD" ;;
+	pnacl)    TARGETS_TO_BUILD="PNaCl $TARGETS_TO_BUILD" ;;
         host) case "$llvm_cv_target_arch" in
             x86)         TARGETS_TO_BUILD="X86 $TARGETS_TO_BUILD" ;;
             x86_64)      TARGETS_TO_BUILD="X86 $TARGETS_TO_BUILD" ;;
@@ -643,6 +644,7 @@
             s390x)       TARGETS_TO_BUILD="SystemZ $TARGETS_TO_BUILD" ;;
             Blackfin)    TARGETS_TO_BUILD="Blackfin $TARGETS_TO_BUILD" ;;
             PTX)         TARGETS_TO_BUILD="PTX $TARGETS_TO_BUILD" ;;
+	    PNaCl)       TARGETS_TO_BUILD="PNaCl $TARGETS_TO_BUILD" ;;
             *)       AC_MSG_ERROR([Can not set target to build]) ;;
           esac ;;
         *) AC_MSG_ERROR([Unrecognized target $a_target]) ;;