Merge pull request #9634 from nojb/ocamlrunparam_comma_fix

Allow ',' at the start of OCAMLRUNPARAM

Changes

@@ -30,6 +30,9 @@ Working version
   (Nicolás Ojeda Bär, review by Stephen Dolan, Gabriel Scherer, Mark Shinwell,
   and Xavier Leroy)
 
+- #9634: Allow initial and repeated commas in `OCAMLRUNPARAM`.
+  (Nicolás Ojeda Bär, review by Gabriel Scherer)
+
 ### Code generation and optimizations:
 
 - #9441: Add RISC-V RV64G native-code backend.

manual/manual/cmds/runtime.etex

@@ -98,6 +98,8 @@ The following environment variables are also consulted:
   (If "OCAMLRUNPARAM" is not set, "CAMLRUNPARAM" will be used instead.)
   This variable must be a sequence of parameter specifications separated
   by commas.
+  For convenience, commas at the beginning of the variable are ignored,
+  and multiple runs of commas are interpreted as a single one.
   A parameter specification is an option letter followed by an "="
   sign, a decimal number (or an hexadecimal number prefixed by "0x"),
   and an optional multiplier.  The options are documented below;

runtime/startup_aux.c

@@ -135,6 +135,7 @@ void caml_parse_ocamlrunparam(void)
       case 'v': scanmult (opt, &caml_verb_gc); break;
       case 'w': scanmult (opt, &caml_init_major_window); break;
       case 'W': scanmult (opt, &caml_runtime_warnings); break;
+      case ',': continue;
       }
       while (*opt != '\0'){
         if (*opt++ == ',') break;