Hi Andrew,
I had edited tools_def.txt file with following changes (shown diff below)
##################
# CLANG38 AARCH64 definitions
##################
-DEFINE CLANG38_AARCH64_TARGET = -target aarch64-linux-gnu
+DEFINE CLANG38_AARCH64_TARGET = -target aarch64-poky-linux
DEFINE CLANG38_AARCH64_CC_FLAGS = DEF(GCC_AARCH64_CC_FLAGS) DEF(CLANG38_AARCH64_TARGET) -mcmodel=small DEF(CLANG38_WARNING_OVERRIDES)
DEFINE CLANG38_AARCH64_DLINK_FLAGS = DEF(CLANG38_AARCH64_TARGET) DEF(GCC_AARCH64_DLINK_FLAGS) -z common-page-size=0x1000
@@ -2767,7 +2767,7 @@ DEFINE CLANG38_AARCH64_DLINK_FLAGS = DEF(CLANG38_AARCH64_TARGET) DEF(GCC_AARCH6
*_CLANG38_AARCH64_ASLCC_FLAGS = DEF(GCC_ASLCC_FLAGS) -fno-lto
*_CLANG38_AARCH64_ASLDLINK_FLAGS = DEF(CLANG38_AARCH64_TARGET) DEF(GCC_AARCH64_ASLDLINK_FLAGS)
*_CLANG38_AARCH64_ASM_FLAGS = DEF(GCC_ASM_FLAGS) DEF(CLANG38_AARCH64_TARGET) $(ARCHASM_FLAGS) $(PLATFORM_FLAGS) -Qunused-arguments
-*_CLANG38_AARCH64_DLINK_FLAGS = DEF(CLANG38_AARCH64_TARGET) DEF(GCC_AARCH64_DLINK_FLAGS) -z common-page-size=0x1000
+*_CLANG38_AARCH64_DLINK_FLAGS = DEF(CLANG38_AARCH64_TARGET) DEF(GCC_AARCH64_DLINK_FLAGS) -z common-page-size=0x1000 -fuse-ld=lld
*_CLANG38_AARCH64_DLINK_XIPFLAGS = -z common-page-size=0x20
*_CLANG38_AARCH64_DLINK2_FLAGS = DEF(GCC_DLINK2_FLAGS_COMMON) -Wl,--defsym=PECOFF_HEADER_SIZE=0x228
*_CLANG38_AARCH64_PLATFORM_FLAGS =