guix: fix glibc 2.27 multiple definition warnings with GCC 10

contrib/guix/manifest.scm

@@ -553,7 +553,8 @@ inspecting signatures in Mach-O binaries.")
                (base32
                 "1b2n1gxv9f4fd5yy68qjbnarhf8mf4vmlxk10i3328c1w5pmp0ca"))
               (patches (search-our-patches "glibc-ldd-x86_64.patch"
-                                           "glibc-2.27-riscv64-Use-__has_include-to-include-asm-syscalls.h.patch"))))))
+                                           "glibc-2.27-riscv64-Use-__has_include-to-include-asm-syscalls.h.patch"
+                                           "glibc-2.27-dont-redefine-nss-database.patch"))))))
 
 (packages->manifest
  (append

contrib/guix/patches/glibc-2.27-dont-redefine-nss-database.patch

@@ -0,0 +1,87 @@
+commit 78a90c2f74a2012dd3eff302189e47ff6779a757
+Author: Andreas Schwab <schwab@linux-m68k.org>
+Date:   Fri Mar 2 23:07:14 2018 +0100
+
+    Fix multiple definitions of __nss_*_database (bug 22918)
+    
+    (cherry picked from commit eaf6753f8aac33a36deb98c1031d1bad7b593d2d)
+
+diff --git a/nscd/gai.c b/nscd/gai.c
+index d081747797..576fd0045b 100644
+--- a/nscd/gai.c
++++ b/nscd/gai.c
+@@ -45,3 +45,6 @@
+ #ifdef HAVE_LIBIDN
+ # include <libidn/idn-stub.c>
+ #endif
++
++/* Some variables normally defined in libc.  */
++service_user *__nss_hosts_database attribute_hidden;
+diff --git a/nss/nsswitch.c b/nss/nsswitch.c
+index d5e655974f..b0f0c11a3e 100644
+--- a/nss/nsswitch.c
++++ b/nss/nsswitch.c
+@@ -62,7 +62,7 @@ static service_library *nss_new_service (name_database *database,
+ 
+ /* Declare external database variables.  */
+ #define DEFINE_DATABASE(name)						      \
+-  extern service_user *__nss_##name##_database attribute_hidden;	      \
++  service_user *__nss_##name##_database attribute_hidden;		      \
+   weak_extern (__nss_##name##_database)
+ #include "databases.def"
+ #undef DEFINE_DATABASE
+diff --git a/nss/nsswitch.h b/nss/nsswitch.h
+index eccb535ef5..63573b9ebc 100644
+--- a/nss/nsswitch.h
++++ b/nss/nsswitch.h
+@@ -226,10 +226,10 @@ libc_hidden_proto (__nss_hostname_digits_dots)
+ #define MAX_NR_ADDRS    48
+ 
+ /* Prototypes for __nss_*_lookup2 functions.  */
+-#define DEFINE_DATABASE(arg)				    \
+-  service_user *__nss_##arg##_database attribute_hidden;    \
+-  int __nss_##arg##_lookup2 (service_user **, const char *, \
+-			     const char *, void **);	    \
++#define DEFINE_DATABASE(arg)						      \
++  extern service_user *__nss_##arg##_database attribute_hidden;		      \
++  int __nss_##arg##_lookup2 (service_user **, const char *,		      \
++			     const char *, void **);			      \
+   libc_hidden_proto (__nss_##arg##_lookup2)
+ #include "databases.def"
+ #undef DEFINE_DATABASE
+diff --git a/posix/tst-rfc3484-2.c b/posix/tst-rfc3484-2.c
+index f509534ca9..8c64ac59ff 100644
+--- a/posix/tst-rfc3484-2.c
++++ b/posix/tst-rfc3484-2.c
+@@ -58,6 +58,7 @@ _res_hconf_init (void)
+ #undef	USE_NSCD
+ #include "../sysdeps/posix/getaddrinfo.c"
+ 
++service_user *__nss_hosts_database attribute_hidden;
+ 
+ /* This is the beginning of the real test code.  The above defines
+    (among other things) the function rfc3484_sort.  */
+diff --git a/posix/tst-rfc3484-3.c b/posix/tst-rfc3484-3.c
+index ae44087a10..1c61aaf844 100644
+--- a/posix/tst-rfc3484-3.c
++++ b/posix/tst-rfc3484-3.c
+@@ -58,6 +58,7 @@ _res_hconf_init (void)
+ #undef	USE_NSCD
+ #include "../sysdeps/posix/getaddrinfo.c"
+ 
++service_user *__nss_hosts_database attribute_hidden;
+ 
+ /* This is the beginning of the real test code.  The above defines
+    (among other things) the function rfc3484_sort.  */
+diff --git a/posix/tst-rfc3484.c b/posix/tst-rfc3484.c
+index 7f191abbbc..8f45848e44 100644
+--- a/posix/tst-rfc3484.c
++++ b/posix/tst-rfc3484.c
+@@ -58,6 +58,7 @@ _res_hconf_init (void)
+ #undef	USE_NSCD
+ #include "../sysdeps/posix/getaddrinfo.c"
+ 
++service_user *__nss_hosts_database attribute_hidden;
+ 
+ /* This is the beginning of the real test code.  The above defines
+    (among other things) the function rfc3484_sort.  */