Allow adding extra flags to LaTeX compiler through environment variable

services/web/app/src/Features/Compile/ClsiManager.mjs

@@ -1066,7 +1066,7 @@ async function _getContentFromMongo(projectId) {
 
 function _finaliseRequest(projectId, options, project, docs, files) {
   const resources = []
-  let flags
+  let flags = []
   let rootResourcePath = options.rootResourcePath
   let rootResourcePathOverride = null
   let hasMainFile = false
@@ -1135,6 +1135,10 @@ function _finaliseRequest(projectId, options, project, docs, files) {
     flags = ['-file-line-error']
   }
 
+  if (process.env.TEX_COMPILER_EXTRA_FLAGS) {
+    flags.push(...process.env.TEX_COMPILER_EXTRA_FLAGS.split(/\s+/).filter(Boolean))
+  }
+
   return {
     compile: {
       options: {