aom: Document nasm min version and ENABLE_NASM option

From afc30689d8d4e18c83d202ce398975ffc7f111a0 Mon Sep 17 00:00:00 2001
From: Wan-Teh Chang <[EMAIL REDACTED]>
Date: Thu, 1 Feb 2024 10:58:45 -0800
Subject: [PATCH] Document nasm min version and ENABLE_NASM option

We need the following change in nasm version 2.14:
  * Changed -I option semantics by adding a trailing path separator
    unconditionally.

See https://nasm.us/doc/nasmdocc.html#section-C.1.12.

Change-Id: I1656f57ff43cb3792e5800afde4ba0c2d54ba4e4
---
 README.md | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 97fb4402a..f81e13e9b 100644
--- a/README.md
+++ b/README.md
@@ -54,9 +54,10 @@ README.md                {#LREADME}
    recommended. A C++ compiler is necessary to build the unit tests and some
    features contained in the examples.
 4. [Perl](https://www.perl.org/).
-5. For x86 targets, [yasm](http://yasm.tortall.net/) or a recent version of
-   [nasm](http://www.nasm.us/). (If both yasm and nasm are present, yasm will
-   be used.) If you download yasm with the intention to work with Visual
+5. For x86 targets, [yasm](http://yasm.tortall.net/) or a recent version (2.14
+   or later) of [nasm](http://www.nasm.us/). (If both yasm and nasm are
+   present, yasm will be used by default. Pass -DENABLE_NASM=ON to cmake to
+   select nasm.) If you download yasm with the intention to work with Visual
    Studio, please download win32.exe or win64.exe and rename it into yasm.exe.
    DO NOT download or use vsyasm.exe.
 6. Building the documentation requires