Add Emscripten auto-install when it's not detected on the system.

Co-authored-by: sigonasr2 <sigonasr2@gmail.com>

C++/scripts/md5

@@ -4,4 +4,4 @@ debug.sh:849488515cab075948653c15eec4177b  -
 lines.sh:3b907786f7fc9204025993016c9080de  -
 release.sh:0ab321c3fa2f1a1b2f03b1aec3bce816  -
 temp:d41d8cd98f00b204e9800998ecf8427e  -
-web.sh:e317e1d492d00517a0ac0e460239daa0  -
+web.sh:ce7a991e69dd9745f057d06430e51a9e  -

C++/scripts/web.sh

@@ -27,4 +27,19 @@ if [[ "$1" == "headless" || "$2" == "headless" ]]; then
     emrun --no_browser ${PROJECT_NAME}.html
 else
     emrun --serve_after_close ${PROJECT_NAME}.html
+fi
+
+if [ $? -eq 127 ]
+then
+    echo "Failed to find Emscripten. Running install script."
+    PWD=$(pwd)
+    cd ..
+    git clone https://github.com/emscripten-core/emsdk.git
+    cd emsdk
+    git pull
+    ./emsdk install latest
+    ./emsdk activate latest
+    source ./emsdk_env.sh
+    cd $PWD
+    echo "Emscripten has been installed. Try running the command again."
 fi