add comments on ~/.emscripten file

tools/settings_template_readonly.py

@@ -5,17 +5,17 @@
 import os
 
 # this helps projects using emscripten find it
-EMSCRIPTEN_ROOT = os.path.expanduser(os.getenv('EMSCRIPTEN') or '{{{ EMSCRIPTEN_ROOT }}}')
-LLVM_ROOT = os.path.expanduser(os.getenv('LLVM') or '{{{ LLVM_ROOT }}}')
-PYTHON = os.path.expanduser(os.getenv('PYTHON') or '{{{ PYTHON }}}')
+EMSCRIPTEN_ROOT = os.path.expanduser(os.getenv('EMSCRIPTEN') or '{{{ EMSCRIPTEN_ROOT }}}') # directory
+LLVM_ROOT = os.path.expanduser(os.getenv('LLVM') or '{{{ LLVM_ROOT }}}') # directory
+PYTHON = os.path.expanduser(os.getenv('PYTHON') or '{{{ PYTHON }}}') # executable
 
 # See below for notes on which JS engine(s) you need
-NODE_JS = os.path.expanduser(os.getenv('NODE') or '{{{ NODE }}}')
+NODE_JS = os.path.expanduser(os.getenv('NODE') or '{{{ NODE }}}') # executable
 SPIDERMONKEY_ENGINE = [
-  os.path.expanduser(os.getenv('SPIDERMONKEY') or 'js'), '-m', '-n']
-V8_ENGINE = os.path.expanduser(os.getenv('V8') or 'd8')
+  os.path.expanduser(os.getenv('SPIDERMONKEY') or 'js'), '-m', '-n'] # executable
+V8_ENGINE = os.path.expanduser(os.getenv('V8') or 'd8') # executable
 
-JAVA = 'java'
+JAVA = 'java' # executable
 
 TEMP_DIR = '/tmp' # You will need to modify this on Windows