Newer versions of ICU requires C++17

The patch is from https://bugs.gentoo.org/934471

Alternative would be to compile without ICU.

Signed-off-by: David Abdurachmanov <davidlt@rivosinc.com>

xalan-c-1.12-icu-75.patch

@@ -0,0 +1,15 @@
+>= ICU 75 needs C++17, see https://bugs.gentoo.org/934471.
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -32,9 +32,9 @@ if (POLICY CMP0067)
+   cmake_policy(SET CMP0067 NEW)
+ endif(POLICY CMP0067)
+ 
+-# Try C++14, then fall back to C++11 and C++98.  Used for feature tests
++# Try C++17, then fall back to C++14, then C++11, and C++98.  Used for feature tests
+ # for optional features.
+-set(CMAKE_CXX_STANDARD 14)
++set(CMAKE_CXX_STANDARD 17)
+ 
+ # Use folders (for IDE project grouping)
+ set_property(GLOBAL PROPERTY USE_FOLDERS ON)

xalan-c.spec

@@ -8,7 +8,7 @@ Version:        1.12.0
 # …but we do not do so because we want to make sure we detect any soversion
 # update.
 %global so_version 112
-Release:        %autorelease
+Release:        %autorelease -e 0.riscv64
 Summary:        Xalan XSLT processor for C/C++
 
 # The entire source is Apache-2.0, except cmake/RunTest.cmake, which is
@@ -26,6 +26,10 @@ Source2:        %{releaseurl}/KEYS
 # Man page hand-written for Fedora in groff_man(7) format based on Xalan -?
 Source3:        Xalan.1
 
+# https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=919d935a4f5068b50598db0ac2beae8460d8f667
+# https://gitweb.gentoo.org/repo/gentoo.git/plain/dev-libs/xalan-c/files/xalan-c-1.12-icu-75.patch
+Patch:          xalan-c-1.12-icu-75.patch
+
 BuildRequires:  gnupg2
 BuildRequires:  cmake
 # Either make or ninja is supported.