Makefile: no bytecode compilation in make world, see make byte instead

 On a machine for which ocamlopt is available, the make world will now
 perform bytecode compilation only in grammar/ (up to the syntax
 extension grammar.cma), and then exclusively use ocamlopt.
 In particular, make world do not build bin/coqtop.byte.
 A separate rule 'make byte' does it, as well as bytecode plugins and
 things like dev/printers.cma.

 'make install' deals only with the part built by 'make', while a new
 rule 'make install-byte' installs the part built by 'make byte'.

 IMPORTANT: PLEASE AVOID doing things like 'make -j world byte' or any
 parallel mix of native and byte rules. These are known to crash sometimes,
 see below. Instead, do rather 'make -j && make -j byte'.

 Indeed, apart from marginal compilation speed-up for users not interested
 in byte versions, the main reason for this commit is to discourage any
 simultaneous use of OCaml native and byte compilers. Indeed, ocamlopt and
 ocamlc will both happily destroy and recreate .cmi for .ml files with no .mli,
 and in case of parallel build this may happen at the very moment another
 ocaml(c|opt) is accessing this .cmi. Until now, this issue has been
 handled via nasty hacks (see the former MLWITHOUTMLI and HACKMLI vars in
 Makefile.build). But these hacks weren't obvious to extend to ocamlopt
 -pack vs. ocamlopt -pack.

 coqdep_boot takes a "-dyndep" option to control precisely how a Declare ML
 Module influences the .v.d dependency file. Possible values are:
 -dyndep opt : regular situation now, depends only on .cmxs
 -dyndep byte : no ocamlopt, or compilation forced to bytecode, depends on .cm(o|a)
 -dyndep both : earlier behavior, dependency over both .cm(o|a) and .cmxs
 -dyndep none : interesting for coqtop with statically linked plugins
 -dyndep var : place Makefile variables $(DYNLIB) and $(DYNOBJ) in .v.d
   instead of extensions .cm*, so that the choice is made in the rest of the
   makefile (see a future commit about coq_makefile)

 NB: two extra mli added to avoid building unecessary .cmo during 'make world',
 without having to use the ocamldep -native option.

 NB: we should state somewhere that coqmktop -top won't work unless
  'make byte' was done first

1 files changed, 14 insertions, 6 deletions

diff --git a/tools/coqdep_common.ml b/tools/coqdep_common.ml
index f5e93527c..bf8bcd0c4 100644
--- a/tools/coqdep_common.ml
+++ b/tools/coqdep_common.ml
@@ -15,7 +15,7 @@ open Minisys
     behavior is the one of [coqdep -boot]. Its only dependencies
     are [Coqdep_lexer], [Unix] and [Minisys], and it should stay so.
     If it need someday some additional information, pass it via
-    options (see for instance [option_natdynlk] below).
+    options (see for instance [option_dynlink] below).
 *)
 
 module StrSet = Set.Make(String)
@@ -26,9 +26,11 @@ module StrListMap = Map.Make(StrList)
 let stderr = Pervasives.stderr
 let stdout = Pervasives.stdout
 
+type dynlink = Opt | Byte | Both | No | Variable
+
 let option_c = ref false
 let option_noglob = ref false
-let option_natdynlk = ref true
+let option_dynlink = ref Both
 let option_boot = ref false
 let option_mldep = ref None
 
@@ -383,10 +385,16 @@ let rec traite_fichier_Coq suffixe verbose f =
        		end) strl
 	  | Declare sl ->
 	      let declare suff dir s =
-		let base = file_name s dir in
-		let opt = if !option_natdynlk then " "^base^".cmxs" else "" in
-		printf " %s%s%s" (escape base) suff opt
-	      in
+		let base = escape (file_name s dir) in
+                match !option_dynlink with
+                | No -> ()
+                | Byte -> printf " %s%s" base suff
+                | Opt -> printf " %s.cmxs" base
+                | Both -> printf " %s%s %s.cmxs" base suff base
+                | Variable ->
+                   printf " %s%s" base
+                    (if suff=".cmo" then "$(DYNOBJ)" else "$(DYNLIB)")
+              in
 	      let decl str =
                 let s = basename_noext str in
 		if not (StrSet.mem s !deja_vu_ml) then begin