Excerpt of a commit in media-libs/x265. If the GNU stack note is not added the
GNU linker assumes the stack is executable by default.
commit 3b49d65f07ce07c68c88fa2ddfbaab295a28ca0b
Author: Vignesh Vijayakumar <vignesh@multicorewareinc.com>
Date:   Thu Nov 2 09:40:41 2017 +0530

    x86: Change assembler from YASM to NASM

    Supports NASM versions 2.13 and greater
--- a/x265/source/common/x86/x86inc.asm
+++ b/x265/source/common/x86/x86inc.asm
@@ -724,6 +724,12 @@ BRANCH_INSTR jz, je, jnz, jne, jl, jle, jnl, jnle, jg, jge, jng, jnge, ja, jae,
 %ifidn __OUTPUT_FORMAT__,elf
 SECTION .note.GNU-stack noalloc noexec nowrite progbits
 %endif
+%ifidn __OUTPUT_FORMAT__,elf32
+section .note.GNU-stack noalloc noexec nowrite progbits
+%endif
+%ifidn __OUTPUT_FORMAT__,elf64
+section .note.GNU-stack noalloc noexec nowrite progbits
+%endif
 
 ; cpuflags