[Bug bootstrap/66448] [6 Regression] Bootstrap fails on darwin after r224161

["iains at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66448

--- Comment #7 from Iain Sandoe <iains at gcc dot gnu.org> ---
Created attachment 35717
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35717&action=edit
pre-proc file for ipa-pure-const.c

svn rev. 224236 + patch to defer declaration of the extern.

If this is an issue with alias support / no alias support, ISTR that Honza has
some trick to turn it off on Linux which makes testing easier.

--- c/l

/GCC/ml/gcc-trunk-apple/./prev-gcc/xg++ -B/GCC/ml/gcc-trunk-apple/./prev-gcc/
-B/compilers/gcc-trunk/x86_64-apple-darwin12/bin/ -nostdinc++
-B/GCC/ml/gcc-trunk-apple/prev-x86_64-apple-darwin12/libstdc++-v3/src/.libs
-B/GCC/ml/gcc-trunk-apple/prev-x86_64-apple-darwin12/libstdc++-v3/libsupc++/.libs

-I/GCC/ml/gcc-trunk-apple/prev-x86_64-apple-darwin12/libstdc++-v3/include/x86_64-apple-darwin12
 -I/GCC/ml/gcc-trunk-apple/prev-x86_64-apple-darwin12/libstdc++-v3/include 
-I/GCC/gcc-trunk/libstdc++-v3/libsupc++
-L/GCC/ml/gcc-trunk-apple/prev-x86_64-apple-darwin12/libstdc++-v3/src/.libs
-L/GCC/ml/gcc-trunk-apple/prev-x86_64-apple-darwin12/libstdc++-v3/libsupc++/.libs
-fno-PIE -c   -g -O2   -gtoggle -DIN_GCC    -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic
-Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common
 -DHAVE_CONFIG_H -I. -I. -I/GCC/gcc-trunk/gcc -I/GCC/gcc-trunk/gcc/.
-I/GCC/gcc-trunk/gcc/../include -I./../intl
-I/GCC/gcc-trunk/gcc/../libcpp/include -I/host/clang42//include 
-I/GCC/gcc-trunk/gcc/../libdecnumber -I/GCC/gcc-trunk/gcc/../libdecnumber/dpd
-I../libdecnumber -I/GCC/gcc-trunk/gcc/../libbacktrace  -I/host/clang42/include
-o ipa-pure-const.o -MT ipa-pure-const.o -MMD -MP -MF
./.deps/ipa-pure-const.TPo /GCC/gcc-trunk/gcc/ipa-pure-const.c -save-temps

-- response.

/GCC/gcc-trunk/gcc/ipa-pure-const.c:1640:1: error:
â{anonymous}::pass_ipa_pure_const::pass_ipa_pure_const(gcc::context*)â defined
but not used [-Werror=unused-function]
 pass_ipa_pure_const::pass_ipa_pure_const(gcc::context *ctxt)