diff --git a/daemon.am b/daemon.am
index abb785592dd364c803a15a8495f9fe102ce4e96a..079f8d3fbda0e5a96d28a3a961481d253de528bc 100644
--- a/daemon.am
+++ b/daemon.am
@@ -25,7 +25,8 @@ CLEANFILES += $(BUILT_SOURCES)
 
 noinst_LIBRARIES = libformat.a libutil.a libstore.a
 
-AM_CXXFLAGS = -Wall
+# Use '-std=c++0x' for 'std::shared_ptr'.
+AM_CXXFLAGS = -Wall -std=c++0x
 
 libformat_a_SOURCES =				\
   nix/boost/format/free_funcs.cc		\
@@ -119,7 +120,7 @@ libstore_a_CPPFLAGS =				\
   -DNIX_BIN_DIR=\"$(bindir)\"			\
   -DOPENSSL_PATH="\"guix-authenticate\""
 
-libstore_a_CXXFLAGS =				\
+libstore_a_CXXFLAGS = $(AM_CXXFLAGS)		\
   $(SQLITE3_CFLAGS) $(LIBGCRYPT_CFLAGS)
 
 bin_PROGRAMS = guix-daemon
diff --git a/nix-upstream b/nix-upstream
index 24cb65efc3c34e24fc653779a4d42cf4f31c6737..e7720aa10a1da63bb15a4587837d649268944943 160000
--- a/nix-upstream
+++ b/nix-upstream
@@ -1 +1 @@
-Subproject commit 24cb65efc3c34e24fc653779a4d42cf4f31c6737
+Subproject commit e7720aa10a1da63bb15a4587837d649268944943