Update //third_party/protobuf to version 3.

third_party/protobuf/m4/acx_check_suncc.m4

+dnl Check for the presence of the Sun Studio compiler.
+dnl If Sun Studio compiler is found, set appropriate flags.
+dnl Additionally, Sun Studio doesn't default to 64-bit by itself,
+dnl nor does it automatically look in standard Solaris places for
+dnl 64-bit libs, so we must add those options and paths to the search
+dnl paths.
+
+dnl TODO(kenton):  This is pretty hacky.  It sets CXXFLAGS, which the autoconf
+dnl docs say should never be overridden except by the user.  It also isn't
+dnl cross-compile safe.  We should fix these problems, but since I don't have
+dnl Sun CC at my disposal for testing, someone else will have to do it.
+
+AC_DEFUN([ACX_CHECK_SUNCC],[
+
+  AC_LANG_PUSH([C++])
+  AC_CHECK_DECL([__SUNPRO_CC], [SUNCC="yes"], [SUNCC="no"])
+  AC_LANG_POP()
+
+
+  AC_ARG_ENABLE([64bit-solaris],
+    [AS_HELP_STRING([--disable-64bit-solaris],
+      [Build 64 bit binary on Solaris @<:@default=on@:>@])],
+             [ac_enable_64bit="$enableval"],
+             [ac_enable_64bit="yes"])
+
+  AS_IF([test "$SUNCC" = "yes" -a "x${ac_cv_env_CXXFLAGS_set}" = "x"],[
+    dnl Sun Studio has a crashing bug with -xO4 in some cases. Keep this
+    dnl at -xO3 until a proper test to detect those crashes can be done.
+    CXXFLAGS="-g0 -xO3 -xlibmil -xdepend -xbuiltin -mt -compat=5 -library=stlport4 -library=Crun -template=no%extdef ${CXXFLAGS}"
+  ])
+
+  case $host_os in
+    *solaris*)
+      AC_CHECK_PROGS(ISAINFO, [isainfo], [no])
+      AS_IF([test "x$ISAINFO" != "xno"],
+            [isainfo_b=`${ISAINFO} -b`],
+            [isainfo_b="x"])
+
+      AS_IF([test "$isainfo_b" != "x"],[
+
+        isainfo_k=`${ISAINFO} -k`
+
+        AS_IF([test "x$ac_enable_64bit" = "xyes"],[
+
+          AC_DEFINE([SOLARIS_64BIT_ENABLED], [1], [64bit enabled])
+          AS_IF([test "x$libdir" = "x\${exec_prefix}/lib"],[
+           dnl The user hasn't overridden the default libdir, so we'll
+           dnl the dir suffix to match solaris 32/64-bit policy
+           libdir="${libdir}/${isainfo_k}"
+          ])
+
+          dnl This should just be set in CPPFLAGS and in LDFLAGS, but libtool
+          dnl does the wrong thing if you don't put it into CXXFLAGS. sigh.
+          dnl (It also needs it in CFLAGS, or it does a different wrong thing!)
+          AS_IF([test "x${ac_cv_env_CXXFLAGS_set}" = "x"],[
+            CXXFLAGS="${CXXFLAGS} -m64"
+            ac_cv_env_CXXFLAGS_set=set
+            ac_cv_env_CXXFLAGS_value='-m64'
+          ])
+
+          AS_IF([test "x${ac_cv_env_CFLAGS_set}" = "x"],[
+            CFLAGS="${CFLAGS} -m64"
+            ac_cv_env_CFLAGS_set=set
+            ac_cv_env_CFLAGS_value='-m64'
+          ])
+
+          AS_IF([test "$target_cpu" = "sparc" -a "x$SUNCC" = "xyes" ],[
+            CXXFLAGS="-xmemalign=8s ${CXXFLAGS}"
+          ])
+        ])
+      ])
+    ;;
+  esac
+
+])