rdkit: Add 2026.3.6 patches

The Conan boost recipe patch applies unchanged to the 2026.03.6 tag.

Author: luhenry

patches/rdkit/2026.3.6/0001-Teach-the-vendored-Conan-boost-recipe-about-riscv64.patch

@@ -0,0 +1,47 @@
+From 014480dbf1d1a961e6e11d8e312aae617cc29151 Mon Sep 17 00:00:00 2001
+From: Ludovic Henry <git@ludovic.dev>
+Date: Thu, 27 Aug 2026 21:36:16 +0200
+Subject: [PATCH] Teach the vendored Conan boost recipe about riscv64
+
+The recipe drives b2 from two arch tables and neither has a riscv64 entry.
+_b2_address_model falls through to "32", so boost is configured as a 32-bit
+build, and _b2_architecture returns None, so no `architecture=` reaches b2.
+Boost.Context selects its stack-switching assembly on
+<architecture>riscv/<address-model>64 (asm/jump_riscv64_sysv_elf_gas.S and
+friends, present since 1.71), so with both unset no asm_sources alternative
+matches and the build has no context implementation to compile.
+
+b2 5.2 already defines the riscv architecture feature and adds no -m32/-m64
+for it, and <abi> defaults to sysv on Linux, so naming the architecture and
+the address model is the whole fix.
+
+conan_boost_mod is a copy of conan-center-index's boost recipe, which has the
+same two gaps.
+
+Upstream-Status: To upstream [the file is a vendored copy of conan-io/conan-center-index's boost recipe; the fix belongs there first and has not been submitted]
+---
+ conan_boost_mod/all/conanfile.py | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/conan_boost_mod/all/conanfile.py b/conan_boost_mod/all/conanfile.py
+index 3cf348b..e89e71e 100644
+--- a/conan_boost_mod/all/conanfile.py
++++ b/conan_boost_mod/all/conanfile.py
+@@ -1149,7 +1149,7 @@ class BoostConan(ConanFile):
+ 
+     @property
+     def _b2_address_model(self):
+-        if self.settings.arch in ("x86_64", "ppc64", "ppc64le", "mips64", "armv8", "armv8.3", "sparcv9"):
++        if self.settings.arch in ("x86_64", "ppc64", "ppc64le", "mips64", "armv8", "armv8.3", "sparcv9", "riscv64"):
+             return "64"
+ 
+         return "32"
+@@ -1185,6 +1185,8 @@ class BoostConan(ConanFile):
+             return "mips1"
+         if str(self.settings.arch).startswith("s390"):
+             return "s390x"
++        if str(self.settings.arch).startswith("riscv"):
++            return "riscv"
+ 
+         return None
+