This patch is needed to build gcc-5.5.0 on the Hurd.

Backported from upstream: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=6cd9cb89ebdc1e1394b81c4a418c2b3b0eb86c57

commit b590b96ebc3f5b42a4829170e069722dd940e2543
Author: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Sat May 9 04:50:23 2015 +0000

            * src/c++98/Makefile.am (AM_CXXFLAGS): Add -std=gnu++98.
            * src/c++98/Makefile.in: Regenerate.
            * src/Makefile.am (AM_CXXFLAGS): Add -std=gnu++98.
            * src/Makefile.in: Regenerate.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@222964 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/libstdc++-v3/src/Makefile.am b/libstdc++-v3/src/Makefile.am
index a5f48b22c6d..cd07ccd81bc 100644
--- a/libstdc++-v3/src/Makefile.am
+++ b/libstdc++-v3/src/Makefile.am
@@ -168,6 +168,7 @@ compatibility-condvar.o: compatibility-condvar.cc
 # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
 # as the occasion calls for it.
 AM_CXXFLAGS = \
+	-std=gnu++98 \
 	$(glibcxx_compiler_pic_flag) \
 	$(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \
 	$(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS)
diff --git a/libstdc++-v3/src/Makefile.in b/libstdc++-v3/src/Makefile.in
index 433f9ea121a..31b56282e26 100644
--- a/libstdc++-v3/src/Makefile.in
+++ b/libstdc++-v3/src/Makefile.in
@@ -429,6 +429,7 @@ libstdc___la_LINK = $(CXXLINK) $(libstdc___la_LDFLAGS)
 # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
 # as the occasion calls for it.
 AM_CXXFLAGS = \
+	-std=gnu++98 \
 	$(glibcxx_compiler_pic_flag) \
 	$(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \
 	$(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS)
diff --git a/libstdc++-v3/src/c++98/Makefile.am b/libstdc++-v3/src/c++98/Makefile.am
index e348dfb1205..a5b68a19a8b 100644
--- a/libstdc++-v3/src/c++98/Makefile.am
+++ b/libstdc++-v3/src/c++98/Makefile.am
@@ -215,6 +215,7 @@ parallel_settings.o: parallel_settings.cc
 # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
 # as the occasion calls for it.
 AM_CXXFLAGS = \
+	-std=gnu++98 \
 	$(glibcxx_lt_pic_flag) $(glibcxx_compiler_shared_flag) \
 	$(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \
 	$(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS)
diff --git a/libstdc++-v3/src/c++98/Makefile.in b/libstdc++-v3/src/c++98/Makefile.in
index 3c69791bb66..ce86136906b 100644
--- a/libstdc++-v3/src/c++98/Makefile.in
+++ b/libstdc++-v3/src/c++98/Makefile.in
@@ -421,6 +421,7 @@ PARALLEL_FLAGS = -D_GLIBCXX_PARALLEL
 # OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
 # as the occasion calls for it.
 AM_CXXFLAGS = \
+	-std=gnu++98 \
 	$(glibcxx_lt_pic_flag) $(glibcxx_compiler_shared_flag) \
 	$(XTEMPLATE_FLAGS) $(VTV_CXXFLAGS) \
 	$(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS)
27e733966cc4a93dfaadd1a761ca1088078baa'>daemon: Use unbranded phrases in comments and messages.</a><span class='msg-avail'>...<span class='msg-tooltip'>* nix/libstore/build.cc, nix/libstore/globals.cc,
nix/libstore/gc.cc, nix/libstore/local-store.cc,
nix/libstore/optimise-store.cc, nix/libstore/store-api.cc,
nix/libutil/archive.cc, nix/nix-daemon/nix-daemon.cc: Replace "Nix
store" by "store", and "Nix daemon" by "build daemon".
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-10-02 23:08:30 +0200'>2018-10-02</span></td><td><a href='/guix/commit/nix/libutil/archive.cc?id=7eca7892014d173ff523417138b90aeff5b7dec1'>daemon: Remove "case hack" for nars.</a><span class='msg-avail'>...<span class='msg-tooltip'>This code has never been of any use in Guix.

* nix/libutil/archive.cc (useCaseHack): Remove.
(parse): Keep only the alternate branch in "if (useCaseHack)".
</span></span></td><td>Ludovic Courtès</td></tr>