grpc: switch to c++17

__thread works better as thread_local for our gcc

net-libs/grpc/grpc-1.41.0.recipe

@@ -6,7 +6,7 @@ connected systems."
 HOMEPAGE="https://grpc.io/"
 COPYRIGHT="2015-2021 The gRPC Authors"
 LICENSE="Apache v2"
-REVISION="2"
+REVISION="3"
 SOURCE_URI="https://github.com/grpc/grpc/archive/v$portVersion/grpc-$portVersion.tar.gz"
 CHECKSUM_SHA256="e5fb30aae1fa1cffa4ce00aa0bbfab908c0b899fcf0bbc30e268367d660d8656"
 PATCHES="grpc-$portVersion.patchset"
@@ -103,6 +103,7 @@ BUILD()
 	cmake -Bbuild -S . \
 		-DCMAKE_BUILD_TYPE=Release \
 		-DCMAKE_INSTALL_PREFIX=$prefix \
+		-DCMAKE_CXX_STANDARD=17 \
 		-DBUILD_SHARED_LIBS=ON \
 		-DgRPC_INSTALL_BINDIR=$relativeBinDir \
 		-DgRPC_INSTALL_INCLUDEDIR=$relativeIncludeDir \

net-libs/grpc/patches/grpc-1.41.0.patchset

@@ -1,4 +1,4 @@
-From 43dcbea98e45c60994137c0dc8b5538dca92cab3 Mon Sep 17 00:00:00 2001
+From 38c91c597e37f36c9a36bf9894f3bfaae2db9ea4 Mon Sep 17 00:00:00 2001
 From: Jerome Duval <jerome.duval@gmail.com>
 Date: Sat, 16 Oct 2021 21:33:26 +0200
 Subject: Haiku: port
@@ -73,6 +73,19 @@ index 8b9831b..d4dad67 100644
  #else
  #error "Could not auto-detect platform"
  #endif
+diff --git a/src/core/lib/gpr/tls.h b/src/core/lib/gpr/tls.h
+index 32add50..63c2616 100644
+--- a/src/core/lib/gpr/tls.h
++++ b/src/core/lib/gpr/tls.h
+@@ -144,7 +144,7 @@ class PthreadTlsImpl : TlsTypeConstrainer<T> {
+ #else
+ 
+ #define GPR_THREAD_LOCAL(type) \
+-  thread_local typename grpc_core::TlsTypeConstrainer<type>::Type
++  __thread typename grpc_core::TlsTypeConstrainer<type>::Type
+ 
+ #endif
+ 
 diff --git a/src/core/lib/iomgr/port.h b/src/core/lib/iomgr/port.h
 index 3e32429..28e9b11 100644
 --- a/src/core/lib/iomgr/port.h