initial buildroot for linux 5.15

package/lld/Config.in.host

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+config BR2_PACKAGE_HOST_LLD
+	bool "host lld"
+	depends on BR2_PACKAGE_LLVM_ARCH_SUPPORTS # llvm
+	help
+	  LLD is a linker from the LLVM project that is a drop-in
+	  replacement for system linkers, and runs much faster than
+	  them. It also provides features that are useful for
+	  toolchain developers.
+
+	  https://lld.llvm.org/

package/lld/lld.hash

@@ -0,0 +1,3 @@
+# locally calculated
+sha256 86262bad3e2fd784ba8c5e2158d7aa36f12b85f2515e95bc81d65d75bb9b0c82  lld-9.0.1.src.tar.xz
+sha256 f7891568956e34643eb6a0db1462db30820d40d7266e2a78063f2fe233ece5a0  LICENSE.TXT

package/lld/lld.mk

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+################################################################################
+#
+# lld
+#
+################################################################################
+
+# LLVM, Clang and lld should be version bumped together
+LLD_VERSION = 9.0.1
+LLD_SITE = https://github.com/llvm/llvm-project/releases/download/llvmorg-$(LLD_VERSION)
+LLD_SOURCE = lld-$(LLD_VERSION).src.tar.xz
+LLD_LICENSE = Apache-2.0 with exceptions
+LLD_LICENSE_FILES = LICENSE.TXT
+LLD_SUPPORTS_IN_SOURCE_BUILD = NO
+HOST_LLD_DEPENDENCIES = host-llvm
+
+# LLVM > 9.0 will soon require C++14 support, building llvm <= 9.0 using a
+# toolchain using gcc < 5.1 gives an error but actually still works. Setting
+# this option makes it still build with gcc >= 4.8.
+# https://reviews.llvm.org/D57264
+HOST_LLD_CONF_OPTS += -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON
+
+# build as static libs as is done in llvm & clang
+HOST_LLD_CONF_OPTS += -DBUILD_SHARED_LIBS=OFF
+
+# GCC looks for tools in a different path from LLD's default installation path
+define HOST_LLD_CREATE_SYMLINKS
+	mkdir -p $(HOST_DIR)/$(GNU_TARGET_NAME)/bin
+	ln -sf $(HOST_DIR)/bin/lld $(HOST_DIR)/$(GNU_TARGET_NAME)/bin/lld
+	ln -sf $(HOST_DIR)/bin/lld $(HOST_DIR)/$(GNU_TARGET_NAME)/bin/ld.lld
+endef
+
+HOST_LLD_POST_INSTALL_HOOKS += HOST_LLD_CREATE_SYMLINKS
+
+$(eval $(host-cmake-package))