This seems to be the magic to insert an endbr64 at the start of global functions. Even though many of these are hidden in the shared library, the majority seems to be called through function pointers that are setup based on the available instruction set extensions.
With this diff "make test" passes again. ok? Index: multimedia/x265/Makefile =================================================================== RCS file: /cvs/ports/multimedia/x265/Makefile,v retrieving revision 1.57 diff -u -p -r1.57 Makefile --- multimedia/x265/Makefile 27 Sep 2023 10:10:22 -0000 1.57 +++ multimedia/x265/Makefile 19 Feb 2024 22:54:22 -0000 @@ -3,7 +3,7 @@ COMMENT= free H.265/HEVC encoder VER= 3.5 DISTNAME= x265_${VER} PKGNAME= x265-${VER} -REVISION= 2 +REVISION= 3 CATEGORIES= multimedia SITES= https://bitbucket.org/multicoreware/x265_git/downloads/ Index: multimedia/x265/patches/patch-source_common_x86_x86inc_asm =================================================================== RCS file: multimedia/x265/patches/patch-source_common_x86_x86inc_asm diff -N multimedia/x265/patches/patch-source_common_x86_x86inc_asm --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ multimedia/x265/patches/patch-source_common_x86_x86inc_asm 19 Feb 2024 22:54:22 -0000 @@ -0,0 +1,13 @@ +Index: source/common/x86/x86inc.asm +--- source/common/x86/x86inc.asm.orig ++++ source/common/x86/x86inc.asm +@@ -717,6 +717,9 @@ BRANCH_INSTR jz, je, jnz, jne, jl, jle, jnl, jnle, jg, + %endif + align function_align + %2: ++ %if ARCH_X86_64 ++ endbr64 ++ %endif + RESET_MM_PERMUTATION ; needed for x86-64, also makes disassembly somewhat nicer + %xdefine rstk rsp ; copy of the original stack pointer, used when greater alignment than the known stack alignment is required + %assign stack_offset 0 ; stack pointer offset relative to the return address