Index: usr.bin/gh-bc/Makefile
===================================================================
--- usr.bin/gh-bc/Makefile
+++ usr.bin/gh-bc/Makefile
@@ -54,8 +54,11 @@
 MAN_SRC_DC=	dc/A.1
 
 # prevent floating point incompatibilities caused by -flto on some architectures
+#
+# External GCC disables LTO on aarch64
 .if ${MACHINE_ARCH} != mips && ${MACHINE_ARCH} != mips64 && \
-    ${MACHINE_ARCH} != powerpc64 && ${MACHINE_ARCH} != riscv64
+    ${MACHINE_ARCH} != powerpc64 && ${MACHINE_ARCH} != riscv64 && \
+    !(${COMPILER_TYPE} == "gcc" && ${MACHINE_ARCH} == "aarch64")
 CFLAGS+=	-flto
 .endif