Revert https://codereview.chromium.org/1291903002 (protobuf roll).

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
-
-])