ci: define TERMUX_VERSION in .github/workflows/termux_ci.yml instead of using -os termux, to make the emulation closer to a real Termux (#25128)

Author: spytheman

.github/workflows/termux_ci.yml

@@ -38,11 +38,15 @@ jobs:
             cp -r /src ~/vproject; cd ~/vproject
             touch inside_docker.txt
             ls -la
+            git log -n4
+            echo "previous TERMUX_VERSION: $TERMUX_VERSION"
+            export TERMUX_VERSION=0.118.3
+            echo "explicit TERMUX_VERSION: $TERMUX_VERSION"
             .github/workflows/retry.sh pkg update -y
             .github/workflows/retry.sh pkg install -y clang libexecinfo libgc libgc-static make git
-            git log -n4
-            VFLAGS="-cc cc -os termux" make
+            VFLAGS="-cc cc" make
             ./v symlink
             v run examples/hello_world.v
             v run examples/primes.v
+            v -e "import os; dump( os.user_os() )"
           '