Recommend a recent version of waf.

Our doc, CLAUDE.md and github tests were using a very old version of
way (not compatible with the recent usage of semaphores by
ae987beb7863683fd).

We now use the versions 2.1.x, and we know the current version (2.1.9)
works fine.

Note that I removed the mention of the version in CLAUDE.md: Claude
should not even try to install waf, it is supposed to run in a working
environment.

Change-Id: I49673be3c5008a51ff700e923b65bde5e194b810
Priv-Id: d4f98b06a27b7d53511e5b7a68ed5a6046089b18

Author: LpZ-squall

.github/workflows/tests.yml

@@ -44,7 +44,7 @@ jobs:
 
       - name: Install waf
         run: |
-          sudo curl https://waf.io/waf-2.0.24 -o /usr/local/bin/waf && \
+          sudo curl https://waf.io/waf-2.1.9 -o /usr/local/bin/waf && \
           sudo chmod +x /usr/local/bin/waf && \
           sudo waf --help 2>&1 >/dev/null
 

CLAUDE.md

@@ -8,7 +8,7 @@ lib-common is an Intersec C library extension targeting Linux environments. It p
 
 ## Build System
 
-lib-common uses WAF (https://waf.io/). Download waf 2.0.x and place in PATH.
+lib-common uses WAF (https://waf.io/).
 
 ```bash
 waf configure              # Configure (default profile)

README.adoc

@@ -91,14 +91,14 @@ install it in a directory already in your PATH environment, for example
 `/usr/local/bin`:
 ---------------------------------
 $ cd /usr/local/bin
-$ wget https://waf.io/waf-2.0.x
-$ ln -s waf-2.0.x waf
-$ chmod +x waf-2.0.x
+$ wget https://waf.io/waf-2.1.x
+$ ln -s waf-2.1.x waf
+$ chmod +x waf-2.1.x
 $ ./waf
 ---------------------------------
 
-`waf` versions 2.0.8 and 2.0.18 are known to work fine, running the latest 2.0.x
-`waf` should also work fine.
+`waf` versions 2.1.9 is known to work fine, but running the latest 2.1.x `waf`
+should also work fine.
 
 === Dependencies
 ==== List of packages per Linux distribution