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Work even with compilers which enable -fstack-protector by default [BZ #7065]
With all the machinery we just added, we can easily arrange to work even when the compiler passes in -fstack-protector automatically: all the necessary bits of glibc are always compiled with -fno-stack-protector now. So tear out the check in configure, and add appropriate calls to -fno-stack-protector in tests that need them (largely those that use -nostdlib), since we don't yet have a __stack_chk_fail that those tests can rely upon. (GCC often provides one, but we cannot rely on this, especially not when bootstrapping.) When stack protection is disabled, explicitly pass -fno-stack-protector to everything, to stop a compiler hacked to enable it from inserting calls to __stack_chk_fail via the PLT in every object file.
This commit is contained in:
Nick Alcock
committed by
Florian Weimer
Florian Weimer
parent
bc174f20b8
commit
66a704c43c
90
configure
vendored
90
configure
vendored
@ -4010,11 +4010,25 @@ elif test "$enable_stack_protector" = strong && test "$libc_cv_ssp_strong" = yes
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stack_protector="-fstack-protector-strong"
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$as_echo "#define STACK_PROTECTOR_LEVEL 3" >>confdefs.h
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else
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stack_protector="-fno-stack-protector"
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$as_echo "#define STACK_PROTECTOR_LEVEL 0" >>confdefs.h
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fi
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if test -n "$stack_protector"; then
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no_ssp=-fno-stack-protector
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else
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no_ssp=
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if test "$enable_stack_protector" != no; then
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as_fn_error $? "--enable-stack-protector=$enable_stack_protector specified, but specified level of stack protection is not supported by the compiler." "$LINENO" 5
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fi
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fi
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# For the multi-arch option we need support in the assembler & linker.
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for assembler and linker STT_GNU_IFUNC support" >&5
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$as_echo_n "checking for assembler and linker STT_GNU_IFUNC support... " >&6; }
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@ -4037,7 +4051,7 @@ __start:
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EOF
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libc_cv_ld_gnu_indirect_function=no
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if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
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-nostartfiles -nostdlib \
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-nostartfiles -nostdlib $no_ssp \
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-o conftest conftest.S 1>&5 2>&5; then
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# Do a link to see if the backend supports IFUNC relocs.
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$READELF -r conftest 1>&5
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@ -5532,7 +5546,7 @@ extern int glibc_conftest_frobozz;
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void _start() { glibc_conftest_frobozz = 1; }
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EOF
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if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
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-nostartfiles -nostdlib \
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-nostartfiles -nostdlib $no_ssp \
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-o conftest conftest.s conftest1.c 1>&5 2>&5; then
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libc_cv_asm_set_directive=yes
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else
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@ -5556,7 +5570,7 @@ else
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int bar __attribute__ ((visibility ("protected"))) = 1;
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EOF
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libc_cv_protected_data=no
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if { ac_try='${CC-cc} -nostdlib -nostartfiles -fPIC -shared conftest.c -o conftest.so'
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if { ac_try='${CC-cc} -nostdlib -nostartfiles $no_ssp -fPIC -shared conftest.c -o conftest.so'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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(eval $ac_try) 2>&5
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ac_status=$?
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@ -5566,7 +5580,7 @@ EOF
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extern int bar;
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int main (void) { return bar; }
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EOF
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if { ac_try='${CC-cc} -nostdlib -nostartfiles conftest.c -o conftest conftest.so'
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if { ac_try='${CC-cc} -nostdlib -nostartfiles $no_ssp conftest.c -o conftest conftest.so'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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(eval $ac_try) 2>&5
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ac_status=$?
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@ -5651,7 +5665,7 @@ __attribute__ ((constructor)) void ctor (void) { asm (""); }
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__attribute__ ((destructor)) void dtor (void) { asm (""); }
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EOF
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -o conftest
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -o conftest
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conftest.c -static -nostartfiles -nostdlib
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1>&5'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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@ -5764,7 +5778,7 @@ extern int mumble;
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int foo (void) { return bar (mumble); }
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EOF
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
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-fPIC -shared -o conftest.so conftest.c
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-fPIC -shared $no_ssp -o conftest.so conftest.c
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-nostdlib -nostartfiles
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-Wl,-z,combreloc 1>&5'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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@ -5800,7 +5814,7 @@ if test x"$gnu_ld" = x"yes"; then
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cat > conftest.c <<EOF
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int _start (void) { return 42; }
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EOF
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
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-Wl,-z,execstack -nostdlib -nostartfiles
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-fPIC -shared -o conftest.so conftest.c
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1>&5'
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@ -5854,7 +5868,7 @@ else
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cat > conftest.c <<EOF
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int _start (void) { return 42; }
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EOF
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
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-fPIC -shared -o conftest.so conftest.c
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-Wl,--hash-style=both -nostdlib 1>&5'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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@ -5947,7 +5961,7 @@ int foo (void) { return mumble; }
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EOF
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
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-fPIC -shared -o conftest.so conftest.c
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-nostdlib -nostartfiles
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-nostdlib -nostartfiles $no_ssp
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1>&5'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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(eval $ac_try) 2>&5
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@ -5975,7 +5989,7 @@ if ${libc_cv_output_format+:} false; then :
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$as_echo_n "(cached) " >&6
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else
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if libc_cv_output_format=`
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${CC-cc} -nostartfiles -nostdlib -Wl,--print-output-format 2>&5`
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${CC-cc} -nostartfiles -nostdlib $no_ssp -Wl,--print-output-format 2>&5`
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then
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:
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else
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@ -6453,60 +6467,6 @@ if test $libc_cv_predef_fortify_source = yes; then
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fi
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC implicitly enables -fstack-protector" >&5
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$as_echo_n "checking whether $CC implicitly enables -fstack-protector... " >&6; }
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if ${libc_cv_predef_stack_protector+:} false; then :
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$as_echo_n "(cached) " >&6
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else
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cat confdefs.h - <<_ACEOF >conftest.$ac_ext
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/* end confdefs.h. */
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extern void foobar (char *);
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int
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main ()
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{
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char large_array[2048]; foobar (large_array);
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;
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return 0;
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}
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_ACEOF
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if ac_fn_c_try_compile "$LINENO"; then :
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libc_undefs=`$NM -u conftest.o |
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LC_ALL=C $AWK '$1 == "U" { print $2 | "sort -u"; next } { exit(1) }' \
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2>&5` || {
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as_fn_error $? "confusing output from $NM -u" "$LINENO" 5
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}
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echo >&5 "libc_undefs='$libc_undefs'"
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# On some architectures, there are architecture-specific undefined
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# symbols (resolved by the linker), so filter out unknown symbols.
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# This will fail to produce the correct result if the compiler
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# defaults to -fstack-protector but this produces an undefined symbol
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# other than __stack_chk_fail or __stack_chk_fail_local. However,
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# compilers like that have not been encountered in practice.
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libc_undefs=`echo "$libc_undefs" | \
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egrep '^(foobar|__stack_chk_fail|__stack_chk_fail_local)$'`
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case "$libc_undefs" in
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foobar) libc_cv_predef_stack_protector=no ;;
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'__stack_chk_fail
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foobar'|'__stack_chk_fail_local
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foobar') libc_cv_predef_stack_protector=yes ;;
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*) as_fn_error $? "unexpected symbols in test: $libc_undefs" "$LINENO" 5 ;;
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esac
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else
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as_fn_error $? "test compilation failed" "$LINENO" 5
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fi
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rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
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fi
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{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_predef_stack_protector" >&5
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$as_echo "$libc_cv_predef_stack_protector" >&6; }
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libc_extra_cflags=
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if test $libc_cv_predef_stack_protector = yes; then
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libc_extra_cflags="$libc_extra_cflags -fno-stack-protector"
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fi
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libc_extra_cppflags=
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# Some linkers on some architectures support __ehdr_start but with
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# bugs. Make sure usage of it does not create relocations in the
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# output (as the linker should resolve them all for us).
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@ -6520,7 +6480,7 @@ old_CFLAGS="$CFLAGS"
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old_LDFLAGS="$LDFLAGS"
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old_LIBS="$LIBS"
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CFLAGS="$CFLAGS -fPIC"
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LDFLAGS="$LDFLAGS -nostdlib -nostartfiles -shared"
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LDFLAGS="$LDFLAGS -nostdlib -nostartfiles -shared $no_ssp"
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LIBS=
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cat confdefs.h - <<_ACEOF >conftest.$ac_ext
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/* end confdefs.h. */
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