add support for DSM 6

spk/dotnet9-runtime/Makefile

@@ -3,9 +3,10 @@ SPK_VERS = 9.0.0
 SPK_REV = 1
 SPK_ICON = src/dotnet.png
 
+OPTIONAL_DEPENDS = cross/libstdc++
 DEPENDS = cross/dotnet9-runtime
 
-REQUIRED_MIN_DSM = 7.0
+REQUIRED_MIN_DSM = 6.0
 
 # Arch exclusions for dotnet
 DOTNET_CORE_ARCHS = 1
@@ -20,7 +21,20 @@ DISPLAY_NAME = .NET 9 runtime
 HOMEPAGE = https://dotnet.microsoft.com/
 LICENSE  = MIT
 
+include ../../mk/spksrc.common.mk
+ifeq ($(call version_lt, ${TCVERSION}, 7.0),1)
+# we do not only need the updated libstdc++ library, we also need to
+# adjust the library search path for dotnet to use this version.
+DEPENDS += cross/libstdc++
+POST_STRIP_TARGET = dotnet_patch_target
+endif
+
 SPK_COMMANDS = share/dotnet/dotnet
 
 include ../../mk/spksrc.spk.mk
 
+.PHONY: dotnet_patch_target
+# Set library path to use bundled libstdc++
+dotnet_patch_target:
+	@$(MSG) "Set library runpath in dotnet executable."
+	@patchelf --set-rpath /var/packages/$(SPK_NAME)/target/lib $(STAGING_DIR)/share/dotnet/dotnet