git.m6w6.name Git - awesomized/libmemcached/blob - m4/ax_harden_compiler_flags.m4

   1 # vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2 # ===========================================================================
   3 #      https://github.com/BrianAker/ddm4/
   4 # ===========================================================================
   5 #
   6 # SYNOPSIS
   7 #
   8 #   AX_HARDEN_COMPILER_FLAGS() AX_HARDEN_LINKER_FLAGS()
   9 #
  10 # DESCRIPTION
  11 #
  12 #   Any compiler flag that "hardens" or tests code. C99 is assumed.
  13 #
  14 #   NOTE: Implementation based on AX_APPEND_FLAG.
  15 #
  16 # LICENSE
  17 #
  18 #  Copyright (C) 2012 Brian Aker
  19 #  All rights reserved.
  20 #
  21 #  Redistribution and use in source and binary forms, with or without
  22 #  modification, are permitted provided that the following conditions are
  23 #  met:
  24 #
  25 #      * Redistributions of source code must retain the above copyright
  26 #  notice, this list of conditions and the following disclaimer.
  27 #
  28 #      * Redistributions in binary form must reproduce the above
  29 #  copyright notice, this list of conditions and the following disclaimer
  30 #  in the documentation and/or other materials provided with the
  31 #  distribution.
  32 #
  33 #      * The names of its contributors may not be used to endorse or
  34 #  promote products derived from this software without specific prior
  35 #  written permission.
  36 #
  37 #  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  38 #  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  39 #  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  40 #  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  41 #  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  42 #  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  43 #  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  44 #  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  45 #  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  46 #  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  47 #  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  48
  49 # The Following flags are not checked for
  50 # -Wdeclaration-after-statement is counter to C99
  51 # _APPEND_COMPILE_FLAGS_ERROR([-std=c++11]) -- Not ready yet
  52 # _APPEND_COMPILE_FLAGS_ERROR([-pedantic]) --
  53 # ?  _APPEND_COMPILE_FLAGS_ERROR([-Wlong-long]) -- Don't turn on for
  54 # compatibility issues memcached_stat_st
  55
  56 #serial 8
  57
  58 AC_DEFUN([_WARNINGS_AS_ERRORS],
  59     [AC_CACHE_CHECK([if all warnings into errors],[ac_cv_warnings_as_errors],
  60       [AS_IF([test "x$ac_cv_vcs_checkout" = xyes],[ac_cv_warnings_as_errors=yes],
  61         [ac_cv_warnings_as_errors=no])
  62       ])
  63     ])
  64
  65 # Note: Should this be LIBS or LDFLAGS?
  66 AC_DEFUN([_APPEND_LINK_FLAGS_ERROR],
  67          [AC_REQUIRE([AX_APPEND_LINK_FLAGS])
  68          AX_APPEND_LINK_FLAGS([$1],[LDFLAGS],[-Werror])
  69          ])
  70
  71 AC_DEFUN([_APPEND_COMPILE_FLAGS_ERROR],
  72          [AC_REQUIRE([AX_APPEND_COMPILE_FLAGS])
  73          AX_APPEND_COMPILE_FLAGS([$1],,[-Werror])
  74          ])
  75
  76 # Everything above this does the heavy lifting, while what follows does the specifics.
  77
  78 AC_DEFUN([_HARDEN_LINKER_FLAGS],
  79          [
  80          AS_IF([test "$CC" != "clang"],
  81            [_APPEND_LINK_FLAGS_ERROR([-z relro -z now])
  82 #_APPEND_LINK_FLAGS_ERROR([-pie])
  83            AS_IF([test "x$ac_cv_warnings_as_errors" = xyes],
  84              [AX_APPEND_LINK_FLAGS([-Werror])])])
  85          ])
  86
  87 AC_DEFUN([_HARDEN_CC_COMPILER_FLAGS],
  88          [AC_LANG_PUSH([C])dnl
  89
  90          AS_IF([test "x$ax_enable_debug" = xyes],
  91            [CFLAGS=''
  92            _APPEND_COMPILE_FLAGS_ERROR([-H])
  93            _APPEND_COMPILE_FLAGS_ERROR([-ggdb])
  94            _APPEND_COMPILE_FLAGS_ERROR([-g])
  95            _APPEND_COMPILE_FLAGS_ERROR([-O0])],
  96            [_APPEND_COMPILE_FLAGS_ERROR([-g])
  97            _APPEND_COMPILE_FLAGS_ERROR([-O2])])
  98
  99          AS_IF([test "x$ac_cv_vcs_checkout" = xyes],
 100            [_APPEND_COMPILE_FLAGS_ERROR([-fstack-check])
 101            _APPEND_COMPILE_FLAGS_ERROR([-Wpragmas])
 102            _APPEND_COMPILE_FLAGS_ERROR([-Wunknown-pragmas])],
 103            [_APPEND_COMPILE_FLAGS_ERROR([-Wno-unknown-pragmas])
 104            _APPEND_COMPILE_FLAGS_ERROR([-Wno-pragmas])])
 105
 106          AS_IF([test "$CC" = "clang"],
 107            [_APPEND_COMPILE_FLAGS_ERROR([-Qunused-arguments])])
 108
 109          _APPEND_COMPILE_FLAGS_ERROR([-Wall])
 110          _APPEND_COMPILE_FLAGS_ERROR([-Wextra])
 111          _APPEND_COMPILE_FLAGS_ERROR([-Wthis-test-should-fail])
 112          _APPEND_COMPILE_FLAGS_ERROR([-std=c99])
 113 # Anything below this comment please keep sorted.
 114 # _APPEND_COMPILE_FLAGS_ERROR([-Wmissing-format-attribute])
 115           _APPEND_COMPILE_FLAGS_ERROR([-Wunsuffixed-float-constants])
 116           _APPEND_COMPILE_FLAGS_ERROR([-Wjump-misses-init])
 117           _APPEND_COMPILE_FLAGS_ERROR([-Wno-attributes])
 118           _APPEND_COMPILE_FLAGS_ERROR([-Waddress])
 119           _APPEND_COMPILE_FLAGS_ERROR([-Wvarargs])
 120           _APPEND_COMPILE_FLAGS_ERROR([-Warray-bounds])
 121           _APPEND_COMPILE_FLAGS_ERROR([-Wbad-function-cast])
 122 # Not in use -Wc++-compat
 123           _APPEND_COMPILE_FLAGS_ERROR([-Wchar-subscripts])
 124           _APPEND_COMPILE_FLAGS_ERROR([-Wcomment])
 125           _APPEND_COMPILE_FLAGS_ERROR([-Wfloat-equal])
 126           _APPEND_COMPILE_FLAGS_ERROR([-Wformat-security])
 127           _APPEND_COMPILE_FLAGS_ERROR([-Wformat=2])
 128           _APPEND_COMPILE_FLAGS_ERROR([-Wformat-y2k])
 129           _APPEND_COMPILE_FLAGS_ERROR([-Wlogical-op])
 130           _APPEND_COMPILE_FLAGS_ERROR([-Wmaybe-uninitialized])
 131           _APPEND_COMPILE_FLAGS_ERROR([-Wmissing-field-initializers])
 132           AS_IF([test "x$MINGW" = xyes],
 133                 [_APPEND_COMPILE_FLAGS_ERROR([-Wno-missing-noreturn])],
 134                 [_APPEND_COMPILE_FLAGS_ERROR([-Wmissing-noreturn])])
 135           _APPEND_COMPILE_FLAGS_ERROR([-Wmissing-prototypes])
 136           _APPEND_COMPILE_FLAGS_ERROR([-Wnested-externs])
 137           _APPEND_COMPILE_FLAGS_ERROR([-Wnormalized=id])
 138           _APPEND_COMPILE_FLAGS_ERROR([-Wold-style-definition])
 139           _APPEND_COMPILE_FLAGS_ERROR([-Woverride-init])
 140           _APPEND_COMPILE_FLAGS_ERROR([-Wpointer-arith])
 141           _APPEND_COMPILE_FLAGS_ERROR([-Wpointer-sign])
 142           AS_IF([test "x$MINGW" = xyes],
 143                 [_APPEND_COMPILE_FLAGS_ERROR([-Wno-suggest-attribute=const])
 144                 _APPEND_COMPILE_FLAGS_ERROR([-Wno-suggest-attribute=noreturn])
 145                 _APPEND_COMPILE_FLAGS_ERROR([-Wno-suggest-attribute=pure])
 146                 _APPEND_COMPILE_FLAGS_ERROR([-Wno-redundant-decls])],
 147                 [_APPEND_COMPILE_FLAGS_ERROR([-Wredundant-decls])])
 148
 149           _APPEND_COMPILE_FLAGS_ERROR([-Wshadow])
 150           _APPEND_COMPILE_FLAGS_ERROR([-Wshorten-64-to-32])
 151           _APPEND_COMPILE_FLAGS_ERROR([-Wsign-compare])
 152           _APPEND_COMPILE_FLAGS_ERROR([-Wstrict-overflow=1])
 153           _APPEND_COMPILE_FLAGS_ERROR([-Wstrict-prototypes])
 154           _APPEND_COMPILE_FLAGS_ERROR([-Wswitch-enum])
 155           _APPEND_COMPILE_FLAGS_ERROR([-Wtrampolines])
 156           _APPEND_COMPILE_FLAGS_ERROR([-Wundef])
 157           _APPEND_COMPILE_FLAGS_ERROR([-Wunsafe-loop-optimizations])
 158           _APPEND_COMPILE_FLAGS_ERROR([-funsafe-loop-optimizations])
 159           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=address])
 160           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=integer])
 161           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=thread])
 162           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=memory])
 163           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=alignment])
 164           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=bool])
 165           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=bounds])
 166           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=enum])
 167           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=float-cast-overflow])
 168           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=float-divide-by-zero])
 169           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=integer-divide-by-zero])
 170           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=null])
 171           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=object-size])
 172           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=return])
 173           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=shift])
 174           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=signed-integer-overflow])
 175           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=unreachable])
 176           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=unsigned-integer-overflow])
 177           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=vla-bound])
 178           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=vptr])
 179           _APPEND_COMPILE_FLAGS_ERROR([-Wclobbered])
 180           _APPEND_COMPILE_FLAGS_ERROR([-Wunused])
 181           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-result])
 182           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-variable])
 183           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-parameter])
 184           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-local-typedefs])
 185           _APPEND_COMPILE_FLAGS_ERROR([-Wwrite-strings])
 186           _APPEND_COMPILE_FLAGS_ERROR([-floop-parallelize-all])
 187           _APPEND_COMPILE_FLAGS_ERROR([-fwrapv])
 188           _APPEND_COMPILE_FLAGS_ERROR([-fmudflapt])
 189           _APPEND_COMPILE_FLAGS_ERROR([-pipe])
 190
 191           AS_IF([test "x$ax_enable_debug" = xno],
 192             [AS_IF([test "x$ac_cv_vcs_checkout" = xyes],
 193               [AS_IF([test "x${target_os}" != "xmingw"],
 194                 [AS_IF([test "x$ac_c_gcc_recent" = xyes],
 195                   [_APPEND_COMPILE_FLAGS_ERROR([-D_FORTIFY_SOURCE=2])
 196                   #_APPEND_COMPILE_FLAGS_ERROR([-Wstack-protector])
 197                   #_APPEND_COMPILE_FLAGS_ERROR([-fstack-protector])
 198                   #_APPEND_COMPILE_FLAGS_ERROR([--param=ssp-buffer-size=1])
 199                   _APPEND_COMPILE_FLAGS_ERROR([-fstack-protector-all])
 200                   ])])])])
 201
 202          AS_IF([test "x$ac_cv_warnings_as_errors" = xyes],
 203              [AX_APPEND_FLAG([-Werror])])
 204
 205           AC_LANG_POP([C])
 206   ])
 207
 208 AC_DEFUN([_HARDEN_CXX_COMPILER_FLAGS],
 209          [AC_LANG_PUSH([C++])
 210          AC_REQUIRE([_APPEND_COMPILE_FLAGS_ERROR])
 211
 212          AS_IF([test "x$ax_enable_debug" = xyes],
 213            [CXXFLAGS=''
 214            _APPEND_COMPILE_FLAGS_ERROR([-H])
 215            _APPEND_COMPILE_FLAGS_ERROR([-ggdb])
 216            _APPEND_COMPILE_FLAGS_ERROR([-g])
 217            _APPEND_COMPILE_FLAGS_ERROR([-O0])],
 218            [_APPEND_COMPILE_FLAGS_ERROR([-g])
 219            _APPEND_COMPILE_FLAGS_ERROR([-O2])])
 220
 221          AS_IF([test "x$ac_cv_vcs_checkout" = xyes],
 222            [_APPEND_COMPILE_FLAGS_ERROR([-fstack-check])
 223            _APPEND_COMPILE_FLAGS_ERROR([-Wpragmas])
 224            _APPEND_COMPILE_FLAGS_ERROR([-Wunknown-pragmas])],
 225            [_APPEND_COMPILE_FLAGS_ERROR([-Wno-unknown-pragmas])
 226            _APPEND_COMPILE_FLAGS_ERROR([-Wno-pragmas])])
 227
 228          AS_IF([test "$CXX" = "clang++"],
 229            [_APPEND_COMPILE_FLAGS_ERROR([-Qunused-arguments])])
 230
 231          _APPEND_COMPILE_FLAGS_ERROR([-Wall])
 232          _APPEND_COMPILE_FLAGS_ERROR([-Wextra])
 233          _APPEND_COMPILE_FLAGS_ERROR([-Wthis-test-should-fail])
 234 # Anything below this comment please keep sorted.
 235 # _APPEND_COMPILE_FLAGS_ERROR([-Wmissing-format-attribute])
 236           _APPEND_COMPILE_FLAGS_ERROR([-Wno-attributes])
 237           _APPEND_COMPILE_FLAGS_ERROR([-Wvarargs])
 238           _APPEND_COMPILE_FLAGS_ERROR([-Waddress])
 239           _APPEND_COMPILE_FLAGS_ERROR([-Warray-bounds])
 240           _APPEND_COMPILE_FLAGS_ERROR([-Wchar-subscripts])
 241           _APPEND_COMPILE_FLAGS_ERROR([-Wcomment])
 242           _APPEND_COMPILE_FLAGS_ERROR([-Wctor-dtor-privacy])
 243           _APPEND_COMPILE_FLAGS_ERROR([-Wfloat-equal])
 244           _APPEND_COMPILE_FLAGS_ERROR([-Wformat=2])
 245           _APPEND_COMPILE_FLAGS_ERROR([-Wformat-y2k])
 246           _APPEND_COMPILE_FLAGS_ERROR([-Wmaybe-uninitialized])
 247           _APPEND_COMPILE_FLAGS_ERROR([-Wmissing-field-initializers])
 248           _APPEND_COMPILE_FLAGS_ERROR([-Wlogical-op])
 249           _APPEND_COMPILE_FLAGS_ERROR([-Wnon-virtual-dtor])
 250           _APPEND_COMPILE_FLAGS_ERROR([-Wnormalized=id])
 251           _APPEND_COMPILE_FLAGS_ERROR([-Woverloaded-virtual])
 252           _APPEND_COMPILE_FLAGS_ERROR([-Wpointer-arith])
 253           AS_IF([test "x$MINGW" = xyes],
 254                 [_APPEND_COMPILE_FLAGS_ERROR([-Wno-suggest-attribute=const])
 255                 _APPEND_COMPILE_FLAGS_ERROR([-Wno-missing-noreturn])
 256                 _APPEND_COMPILE_FLAGS_ERROR([-Wmissing-noreturn])
 257                 _APPEND_COMPILE_FLAGS_ERROR([-Wno-suggest-attribute=noreturn])
 258                 _APPEND_COMPILE_FLAGS_ERROR([-Wno-error=suggest-attribute=noreturn])
 259                 _APPEND_COMPILE_FLAGS_ERROR([-Wno-redundant-decls])],
 260                 [_APPEND_COMPILE_FLAGS_ERROR([-Wredundant-decls])])
 261           _APPEND_COMPILE_FLAGS_ERROR([-Wshadow])
 262           _APPEND_COMPILE_FLAGS_ERROR([-Wshorten-64-to-32])
 263           _APPEND_COMPILE_FLAGS_ERROR([-Wsign-compare])
 264           _APPEND_COMPILE_FLAGS_ERROR([-Wstrict-overflow=1])
 265           _APPEND_COMPILE_FLAGS_ERROR([-Wswitch-enum])
 266           _APPEND_COMPILE_FLAGS_ERROR([-Wtrampolines])
 267           _APPEND_COMPILE_FLAGS_ERROR([-Wundef])
 268           _APPEND_COMPILE_FLAGS_ERROR([-Wunsafe-loop-optimizations])
 269           _APPEND_COMPILE_FLAGS_ERROR([-funsafe-loop-optimizations])
 270           _APPEND_COMPILE_FLAGS_ERROR([-Wc++11-compat])
 271           _APPEND_COMPILE_FLAGS_ERROR([-Weffc++])
 272           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=address])
 273           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=integer])
 274           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=thread])
 275           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=memory])
 276           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=alignment])
 277           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=bool])
 278           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=bounds])
 279           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=enum])
 280           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=float-cast-overflow])
 281           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=float-divide-by-zero])
 282           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=integer-divide-by-zero])
 283           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=null])
 284           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=object-size])
 285           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=return])
 286           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=shift])
 287           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=signed-integer-overflow])
 288           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=unreachable])
 289           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=unsigned-integer-overflow])
 290           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=vla-bound])
 291           _APPEND_COMPILE_FLAGS_ERROR([-fsanitize=vptr])
 292           _APPEND_COMPILE_FLAGS_ERROR([-Wold-style-cast])
 293           _APPEND_COMPILE_FLAGS_ERROR([-Wclobbered])
 294           _APPEND_COMPILE_FLAGS_ERROR([-Wunused])
 295           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-result])
 296           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-variable])
 297           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-parameter])
 298           _APPEND_COMPILE_FLAGS_ERROR([-Wunused-local-typedefs])
 299           _APPEND_COMPILE_FLAGS_ERROR([-Wwrite-strings])
 300           _APPEND_COMPILE_FLAGS_ERROR([-Wformat-security])
 301           _APPEND_COMPILE_FLAGS_ERROR([-floop-parallelize-all])
 302           _APPEND_COMPILE_FLAGS_ERROR([-fwrapv])
 303           _APPEND_COMPILE_FLAGS_ERROR([-fmudflapt])
 304           _APPEND_COMPILE_FLAGS_ERROR([-pipe])
 305
 306           AS_IF([test "x$ax_enable_debug" = xno],
 307           [AS_IF([test "x$ac_cv_vcs_checkout" = xyes],
 308             [AS_IF([test "x${target_os}" != "xmingw"],
 309               [AS_IF([test "x$ac_c_gcc_recent" = xyes],
 310                 [_APPEND_COMPILE_FLAGS_ERROR([-D_FORTIFY_SOURCE=2])
 311                 #_APPEND_COMPILE_FLAGS_ERROR([-Wstack-protector])
 312                 #_APPEND_COMPILE_FLAGS_ERROR([-fstack-protector])
 313                 #_APPEND_COMPILE_FLAGS_ERROR([--param=ssp-buffer-size=1])
 314                 _APPEND_COMPILE_FLAGS_ERROR([-fstack-protector-all])
 315                 ])])])])
 316
 317           AS_IF([test "x$ac_cv_warnings_as_errors" = xyes],
 318                 [AX_APPEND_FLAG([-Werror])])
 319           AC_LANG_POP([C++])
 320   ])
 321
 322 # All of the heavy lifting happens in _HARDEN_LINKER_FLAGS,
 323 # _HARDEN_CC_COMPILER_FLAGS, _HARDEN_CXX_COMPILER_FLAGS
 324   AC_DEFUN([AX_HARDEN_COMPILER_FLAGS],
 325            [AC_PREREQ([2.63])dnl
 326            AC_REQUIRE([_WARNINGS_AS_ERRORS])
 327            AC_REQUIRE([AX_APPEND_LINK_FLAGS])
 328            AC_REQUIRE([AX_COMPILER_VERSION])
 329            AC_REQUIRE([AX_DEBUG])
 330            AC_REQUIRE([AX_VCS_CHECKOUT])
 331
 332            AC_REQUIRE([gl_VISIBILITY])
 333            AS_IF([test -n "$CFLAG_VISIBILITY"],[CPPFLAGS="$CPPFLAGS $CFLAG_VISIBILITY"])
 334
 335            AC_REQUIRE([_HARDEN_LINKER_FLAGS])
 336            AC_REQUIRE([_HARDEN_CC_COMPILER_FLAGS])
 337            AC_REQUIRE([_HARDEN_CXX_COMPILER_FLAGS])
 338            ])