gnu: jsoncpp: Fix test failure on armhf-linux and aarch64-linux.

* gnu/packages/patches/jsoncpp-fix-inverted-case.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/serialization.scm (jsoncpp)[source](patches): New field.

gnu/local.mk

@@ -1030,6 +1030,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/jbig2dec-ignore-testtest.patch		\
   %D%/packages/patches/jfsutils-add-sysmacros.patch		\
   %D%/packages/patches/jfsutils-include-systypes.patch		\
+  %D%/packages/patches/jsoncpp-fix-inverted-case.patch		\
   %D%/packages/patches/kdbusaddons-kinit-file-name.patch	\
   %D%/packages/patches/libnftnl-dont-check-NFTNL_FLOWTABLE_SIZE.patch	\
   %D%/packages/patches/libvirt-create-machine-cgroup.patch	\

gnu/packages/patches/jsoncpp-fix-inverted-case.patch

@@ -0,0 +1,22 @@
+This patch fixes a bug and related test failure on platforms where 'char'
+is unsigned.
+
+Taken from upstream:
+https://github.com/open-source-parsers/jsoncpp/commit/f11611c8785082ead760494cba06196f14a06dcb
+
+diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
+index 8e06cca2..56195dc1 100644
+--- a/src/lib_json/json_writer.cpp
++++ b/src/lib_json/json_writer.cpp
+@@ -178,8 +178,9 @@ static bool isAnyCharRequiredQuoting(char const* s, size_t n) {
+ 
+   char const* const end = s + n;
+   for (char const* cur = s; cur < end; ++cur) {
+-    if (*cur == '\\' || *cur == '\"' || *cur < ' ' ||
+-        static_cast<unsigned char>(*cur) < 0x80)
++    if (*cur == '\\' || *cur == '\"' ||
++        static_cast<unsigned char>(*cur) < ' ' ||
++        static_cast<unsigned char>(*cur) >= 0x80)
+       return true;
+   }
+   return false;

gnu/packages/serialization.scm

@@ -290,6 +290,7 @@ (define-public jsoncpp
               (method git-fetch)
               (uri (git-reference (url home-page) (commit version)))
               (file-name (git-file-name name version))
+              (patches (search-patches "jsoncpp-fix-inverted-case.patch"))
               (sha256
                (base32
                 "037d1b1qdmn3rksmn1j71j26bv4hkjv7sn7da261k853xb5899sg"))))