gnu: libextractor: Adapt to exiv2 0.27.

This fixes a compilation error.

* gnu/packages/patches/libextractor-exiv2.patch: New file.
* gnu/packages/gnunet.scm (libextractor)[sources]: Use it.
* gnu/local.mk (dist_patch_DATA): Add it.

gnu/local.mk

@@ -1016,6 +1016,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/libexif-CVE-2016-6328.patch		\
   %D%/packages/patches/libexif-CVE-2017-7544.patch		\
   %D%/packages/patches/libexif-CVE-2018-20030.patch		\
+  %D%/packages/patches/libextractor-exiv2.patch			\
   %D%/packages/patches/libgcrypt-make-yat2m-reproducible.patch	\
   %D%/packages/patches/libgit2-avoid-python.patch		\
   %D%/packages/patches/libgit2-mtime-0.patch			\

gnu/packages/gnunet.scm

@@ -75,7 +75,8 @@
                                 version ".tar.gz"))
             (sha256
              (base32
-              "1zz2zvikvfibxnk1va3kgzs7djsmiqy7bmk8y01vbsf54ryjb3zh"))))
+              "1zz2zvikvfibxnk1va3kgzs7djsmiqy7bmk8y01vbsf54ryjb3zh"))
+            (patches (search-patches "libextractor-exiv2.patch"))))
    (build-system gnu-build-system)
    ;; WARNING: Checks require /dev/shm to be in the build chroot, especially
    ;; not to be a symbolic link to /run/shm.

gnu/packages/patches/libextractor-exiv2.patch

@@ -0,0 +1,124 @@
+This patch allows us to build libextractor against exiv2 0.27.x.
+Adapted from this upstream commit:
+
+  commit 1ecee9a47717e36cb8a3925d011d1a6de11d631c
+  Author: Christian Grothoff <christian@grothoff.org>
+  Date:   Mon Jul 29 17:58:18 2019 +0200
+
+      importing patch from Gentoo/AS to address exiv2 build issue (#5820)
+
+diff --git a/src/plugins/exiv2_extractor.cc b/src/plugins/exiv2_extractor.cc
+index 8741d40..ef402a8 100644
+--- a/src/plugins/exiv2_extractor.cc
++++ b/src/plugins/exiv2_extractor.cc
+@@ -27,10 +27,7 @@
+ #include <cassert>
+ #include <cstring>
+ #include <math.h>
+-#include <exiv2/exif.hpp>
+-#include <exiv2/error.hpp>
+-#include <exiv2/image.hpp>
+-#include <exiv2/futils.hpp>
++#include <exiv2/exiv2.hpp>
+ 
+ /**
+  * Enable debugging to get error messages.
+@@ -180,7 +177,7 @@ public:
+    *
+    * @return -1 on error
+    */
+-#if EXIV2_VERSION >= EXIV2_MAKE_VERSION(0,26,0)
++#if EXIV2_TEST_VERSION(0,26,0)
+   virtual size_t size (void) const;
+ #else
+   virtual long int size (void) const;
+@@ -316,7 +313,11 @@ ExtractorIO::getb ()
+   const unsigned char *r;
+ 
+   if (1 != ec->read (ec->cls, &data, 1))
++#if EXIV2_TEST_VERSION(0,27,0)
++    throw Exiv2::BasicError<char> (Exiv2::kerDecodeLangAltQualifierFailed);
++#else
+     throw Exiv2::BasicError<char> (42 /* error code */);
++#endif
+   r = (const unsigned char *) data;
+   return *r;
+ }
+@@ -371,7 +372,11 @@ ExtractorIO::putb (Exiv2::byte data)
+ void
+ ExtractorIO::transfer (Exiv2::BasicIo& src)
+ {
++#if EXIV2_TEST_VERSION(0,27,0)
++    throw Exiv2::BasicError<char> (Exiv2::kerDecodeLangAltQualifierFailed);
++#else
+   throw Exiv2::BasicError<char> (42 /* error code */);
++#endif
+ }
+ 
+ 
+@@ -416,7 +421,11 @@ ExtractorIO::seek (long offset,
+ Exiv2::byte *
+ ExtractorIO::mmap (bool isWritable)
+ {
++#if EXIV2_TEST_VERSION(0,27,0)
++    throw Exiv2::BasicError<char> (Exiv2::kerDecodeLangAltQualifierFailed);
++#else
+   throw Exiv2::BasicError<char> (42 /* error code */);
++#endif
+ }
+ 
+ 
+@@ -449,7 +458,7 @@ ExtractorIO::tell (void) const
+  *
+  * @return -1 on error
+  */
+-#if EXIV2_VERSION >= EXIV2_MAKE_VERSION(0,26,0)
++#if EXIV2_TEST_VERSION(0,26,0)
+ size_t
+ #else
+ long int
+@@ -504,7 +513,11 @@ ExtractorIO::eof () const
+ std::string
+ ExtractorIO::path () const
+ {
++#if EXIV2_TEST_VERSION(0,27,0)
++    throw Exiv2::BasicError<char> (Exiv2::kerDecodeLangAltQualifierFailed);
++#else
+   throw Exiv2::BasicError<char> (42 /* error code */);
++#endif
+ }
+ 
+ 
+@@ -517,7 +530,11 @@ ExtractorIO::path () const
+ std::wstring
+ ExtractorIO::wpath () const
+ {
++#if EXIV2_TEST_VERSION(0,27,0)
++    throw Exiv2::BasicError<char> (Exiv2::kerDecodeLangAltQualifierFailed);
++#else
+   throw Exiv2::BasicError<char> (42 /* error code */);
++#endif
+ }
+ #endif
+ 
+@@ -531,7 +548,11 @@ Exiv2::BasicIo::AutoPtr
+ ExtractorIO::temporary () const
+ {
+   fprintf (stderr, "throwing temporary error\n");
++#if EXIV2_TEST_VERSION(0,27,0)
++    throw Exiv2::BasicError<char> (Exiv2::kerDecodeLangAltQualifierFailed);
++#else
+   throw Exiv2::BasicError<char> (42 /* error code */);
++#endif
+ }
+ 
+ 
+@@ -697,7 +718,7 @@ EXTRACTOR_exiv2_extract_method (struct EXTRACTOR_ExtractContext *ec)
+ {
+   try
+     {
+-#if EXIV2_MAKE_VERSION(0,23,0) <= EXIV2_VERSION
++#if !EXIV2_TEST_VERSION(0,24,0)
+       Exiv2::LogMsg::setLevel (Exiv2::LogMsg::mute);
+ #endif
+       std::auto_ptr<Exiv2::BasicIo> eio(new ExtractorIO (ec));