tweak the pdflatex finding code to work in drracket when

started from the finder

original commit: 02e33983d0d6cf2da5a967077bfcb7fff95320f5

pkgs/scribble-pkgs/scribble-lib/scribble/private/run-pdflatex.rkt

@@ -5,12 +5,8 @@
 (provide run-pdflatex)
 
 (define (run-pdflatex file [notify void])
-  (define (err fmt . args) (apply error 'run-pdflatex fmt args))
   (define cmd
-    (list (or (find-executable-path "pdflatex")
-              (and (eq? 'windows (system-type))
-                   (find-executable-path "pdflatex.exe"))
-              (err "could not find a `pdflatex' executable"))
+    (list (get-pdflatex-binary)
           "-interaction=batchmode"
           (format "~a" file)))
   (define logfile (path-replace-suffix file #".log"))
@@ -41,3 +37,26 @@
            (notify "WARNING: no \"Rerun\" found in first run of pdflatex for ~a"
                    file)]))
   (path-replace-suffix file #".pdf"))
+
+(define (get-pdflatex-binary)
+  (define ans
+    (case (system-type)
+      [(macosx) (or (find-executable-path "pdflatex")
+                    (for/or ([macosx-candidate (in-list macosx-candidates)])
+                      (and (file-exists? macosx-candidate)
+                           macosx-candidate)))]
+      [(windows) (or (find-executable-path "pdflatex")
+                     (find-executable-path "pdflatex.exe"))]
+      [(unix) (find-executable-path "pdflatex")]))
+  (unless ans
+    (err "could not find a `pdflatex' executable"))
+  ans)
+
+(define (err fmt . args) (apply error 'run-pdflatex fmt args))
+
+;; under mac os x, gui apps do not get started with
+;; a good path environment, so put likely candidates
+;; for a latex installation here so that the "scribble
+;; pdf" button is more likely to work in drracket
+(define macosx-candidates
+  '("/usr/texbin/pdflatex"))