gnu: perl-www-curl: Fix build failure.

* gnu/packages/patches/perl-www-curl-remove-symbol.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/web.scm (perl-www-curl)[source]: Use it.

gnu/local.mk

@@ -751,6 +751,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/perl-no-sys-dirs.patch			\
   %D%/packages/patches/perl-module-pluggable-search.patch	\
   %D%/packages/patches/perl-reproducible-build-date.patch	\
+  %D%/packages/patches/perl-www-curl-remove-symbol.patch	\
   %D%/packages/patches/pidgin-add-search-path.patch		\
   %D%/packages/patches/pinball-const-fix.patch			\
   %D%/packages/patches/pinball-cstddef.patch			\

gnu/packages/patches/perl-www-curl-remove-symbol.patch

@@ -0,0 +1,39 @@
+Fix build failure caused by erroneous use of an undeclared symbol.
+
+Patch copied from upstream bug report:
+https://rt.cpan.org/Public/Bug/Display.html?id=117793
+
+From 0be0223422e6e5f4091c6e4e058d213623eed105 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
+Date: Mon, 12 Sep 2016 14:40:44 +0200
+Subject: [PATCH] Skip preprocessor symbol only CURL_STRICTER
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+CURL_STRICTER leaked into curl-constants.c when building against
+curl-7.50.2. This is a preprocessor only macro without a value.
+
+CPAN RT#117793
+
+Signed-off-by: Petr Písař <ppisar@redhat.com>
+---
+ Makefile.PL | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Makefile.PL b/Makefile.PL
+index f9170bb..ad2bd3d 100644
+--- a/Makefile.PL
++++ b/Makefile.PL
+@@ -127,7 +127,7 @@ if (!defined($curl_h)) {
+     close H;
+ 
+     for my $e (sort @syms) {
+-       if($e =~ /(OBSOLETE|^CURL_EXTERN|_LAST\z|_LASTENTRY\z)/) {
++       if($e =~ /(OBSOLETE|^CURL_EXTERN|^CURL_STRICTER\z|_LAST\z|_LASTENTRY\z)/) {
+           next;
+        }
+        my ($group) = $e =~ m/^([^_]+_)/;
+-- 
+2.7.4
+

gnu/packages/web.scm

@@ -3053,6 +3053,7 @@ (define-public perl-www-curl
               (uri (string-append
                     "mirror://cpan/authors/id/S/SZ/SZBALINT/WWW-Curl-"
                     version".tar.gz"))
+              (patches (search-patches "perl-www-curl-remove-symbol.patch"))
               (sha256
                (base32
                 "1fmp9aib1kaps9vhs4dwxn7b15kgnlz9f714bxvqsd1j1q8spzsj"))))