Proper linking flags!

makefiles/mlang.mk

@@ -48,13 +48,12 @@ dune: FORCE
 ifeq ($(call is_in,),)
 	$(call make_in,,$@)
 else
-	dune build $(DUNE_OPTIONS)
+	LINKING_MODE=$(LINKING_MODE) dune build $(DUNE_OPTIONS)
 endif
 
 build: FORCE | format dune
 
-# Run only in an opam switch with musl and static options activated
-build-static: DUNE_OPTIONS+=--profile=static 
+build-static: LINKING_MODE=static
 build-static: FORCE build
 
 ##################################################

src/dune

@@ -3,13 +3,17 @@
   (flags
    (:standard -warn-error -A))))
 
+(rule
+ (with-stdout-to
+  linking-flags-mlang.sexp
+  (run ./gen-linking-flags.sh %{env:LINKING_MODE=dynamic}
+    %{ocaml-config:system})))
+
 (executable
  (name main)
  (package mlang)
  (public_name mlang)
- (libraries mlang)
  (flags
-  (:standard -verbose -noautolink -cclib -Wl,-Bstatic -cclib -lgmp_caml
-    -cclib -lmpfr -cclib -lgmp -cclib -lcamlidl -cclib -lnums -cclib
-    -lthreadsnat -cclib -lparmap_stubs -cclib -lANSITerminal_stubs -cclib
-    -Wl,-Bdynamic -cclib -lpthread -cclib -lunix -cclib -ldl)))
+  (:standard
+   (:include linking-flags-mlang.sexp)))
+ (libraries mlang))

src/gen-linking-flags.sh

@@ -0,0 +1,41 @@
+#!/bin/sh
+set -ue
+
+# Copied on https://ocamlpro.com/fr/blog/2021_09_02_generating_static_and_portable_executables_with_ocaml/
+
+LINKING_MODE="$1"
+OS="$2"
+FLAGS=
+CCLIB=
+
+case "$LINKING_MODE" in
+    '')
+        ;; # No extra flags needed
+    static)
+        case "$OS" in
+            linux)
+                FLAGS="-noautolink"
+                CCLIB="-Wl,-Bstatic -lgmp_caml -lmpfr -lgmp -lnums \
+                       -lthreadsnat -lparmap_stubs -lANSITerminal_stubs \
+                       -Wl,-Bdynamic -lpthread -lunix"
+                LIBS=""
+                OCAML_LIBS="camlidl"
+                for lib in $LIBS; do
+                    CCLIB="$CCLIB $(pkg-config $lib --variable libdir)/$lib.a"
+                done
+                for lib in $OCAML_LIBS; do
+                    CCLIB="$CCLIB $(ocamlfind query $lib)/lib$lib.a"
+                done;;
+            *)
+                echo "No known static compilation flags for '$OS'" >&2
+                exit 1
+        esac;;
+    *)
+        echo "Invalid linking mode '$LINKING_MODE'" >&2
+        exit 2
+esac
+
+echo '('
+for f in $FLAGS; do echo "  $f"; done
+for f in $CCLIB; do echo "  -cclib $f"; done
+echo ')'