qpid-proton: build as C++17 to fix jsoncpp link failure (#33025)

jsoncpp >= 1.9.6 (MacPorts ships 1.9.7) only exports its std::string_view
overloads when built as C++17, e.g. Json::Value::get(std::string_view,
const Value&). qpid-proton 0.39.0 hardcodes CMAKE_CXX_STANDARD 11, so its
C++ binding compiles against the removed const char* overloads and fails
to link:

  Undefined symbols for architecture arm64:
    "Json::Value::get(char const*, Json::Value const&) const",
        referenced from: proton::parse(...) in connect_config.cpp.o

Patch the bundled CMakeLists.txt to build as C++17 and bump
compiler.cxx_standard to 2017 so the binding matches the jsoncpp ABI.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

net/qpid-proton/Portfile

@@ -8,7 +8,7 @@ PortGroup           cmake 1.1
 github.setup        apache qpid-proton 0.39.0
 # Change github.tarball_from to 'releases' or 'archive' next update
 github.tarball_from tarball
-revision            1
+revision            2
 
 description         Qpid Proton is a high-performance, lightweight AMQP \
                     1.0 messaging library.
@@ -36,7 +36,7 @@ depends_lib-append  port:jsoncpp \
 cmake.build_type    RelWithDebInfo
 
 compiler.c_standard    1999
-compiler.cxx_standard  2011
+compiler.cxx_standard  2017
 
 # Enabling lto may break the build, avoid it by default.
 configure.args-append \
@@ -57,6 +57,11 @@ configure.args-append \
 # https://github.com/apache/qpid-proton/commit/6f2fdeb633575114c5f92f1387a21eba992b422a
 patchfiles-append   patch-fix-macOS-build.diff
 
+# Build as C++17: jsoncpp (>= 1.9.6) only exports its std::string_view ABI when
+# built as C++17, but qpid-proton 0.39.0 hardcodes C++11, which references the
+# removed const char* Json::Value::get() overloads and fails to link.
+patchfiles-append   patch-cxx17-jsoncpp.diff
+
 test.cmd            ${filespath}/runtests.sh
 test.run            yes                                                 
 

net/qpid-proton/files/patch-cxx17-jsoncpp.diff

@@ -0,0 +1,13 @@
+--- CMakeLists.txt.orig
++++ CMakeLists.txt
+@@ -76,7 +76,9 @@
+   enable_language(CXX)
+
+   # This effectively checks for cmake version 3.1 or later
+-  set(CMAKE_CXX_STANDARD 11)
++  # jsoncpp (>= 1.9.6) exposes a std::string_view ABI under C++17; building the
++  # C++ binding as C++11 references removed const char* overloads -> link errors.
++  set(CMAKE_CXX_STANDARD 17)
+   set(CMAKE_CXX_EXTENSIONS OFF)
+ endif()
+