Use latexmk only if perl is available as well

1. Additional check for perl being present as it is required to run latexmk.
2. Extend comment about TeXLive's `texpath` value to explicitly point to
   its bundled perl interpreter. May help those, who don't have Perl installed
   globally on Windows.

Author: deathaxe

LaTeXTools.sublime-settings

@@ -261,8 +261,8 @@
 
 	"windows": {
 		// Path used when invoking tex & friends; "" is fine for MiKTeX
-		// For TeXlive 2011 (or other years) use
-		// "texpath" : "C:\\texlive\\2011\\bin\\win32;$PATH",
+		// For TeXlive 2025 (or other years) use
+		// "texpath" : "C:\\TexLive\\2025\\bin\\windows;C:\\TexLive\\2025\\tlpkg\\tlperl\\bin;$PATH",
 		"texpath" : "",
 		// TeX distro: "miktex" or "texlive"
 		"distro" : "miktex",

plugins/builder/traditional_builder.py

@@ -52,7 +52,7 @@ def commands(self) -> CommandGenerator:
         if not cmd:
             # prefer latexmk, if available, fallback to texify
             texpath = None if self.env is None else self.env.get("PATH")
-            if shutil.which("latexmk", path=texpath):
+            if shutil.which("latexmk", path=texpath) and shutil.which("perl", path=texpath):
                 cmd = DEFAULT_COMMAND_LATEXMK.copy()
             else:
                 cmd = DEFAULT_COMMAND_TEXIFY.copy()