[make] do not install tuareg if emacs is not found

Summary: Tuareg is only useful for emacs, and `opam install tuareg` fails if emacs is not found.

Reviewed By: mbouaziz

Differential Revision: D6098693

fbshipit-source-id: 167628a

Makefile

@@ -572,7 +572,11 @@ opam.lock: opam
 # This is a magical version number that doesn't reinstall the world when added on top of what we
 # have in opam.lock. To upgrade this version number, manually try to install several utop versions
 # until you find one that doesn't recompile the world. TODO(t20828442): get rid of magic
-OPAM_DEV_DEPS = ocp-indent merlin tuareg utop.2.0.1
+OPAM_DEV_DEPS = ocp-indent merlin utop.2.0.1
+
+ifneq ($(EMACS),no)
+OPAM_DEV_DEPS += tuareg
+endif
 
 .PHONY: devsetup
 devsetup: Makefile.autoconf

Makefile.autoconf.in

@@ -25,6 +25,7 @@ CXX = @CXX@
 CXXFLAGS = @CXXFLAGS@
 # this is useless but autoconf is picky...
 datarootdir = @datarootdir@
+EMACS = @EMACS@
 ENABLE_OCAMLOPT_CUSTOM_CC = @ENABLE_OCAMLOPT_CUSTOM_CC@
 ENABLE_OCAML_BINANNOT = @ENABLE_OCAML_BINANNOT@
 exec_prefix = @exec_prefix@

configure.ac

@@ -289,6 +289,7 @@ AC_SUBST([NCPU])
 
 AC_CHECK_TOOL([ANT], [ant], [no])
 AC_CHECK_TOOL([BUCK], [buck], [no])
+AC_CHECK_TOOL([EMACS], [emacs], [no])
 AC_ARG_VAR([MVN], [command to execute Maven when running tests])
 AS_IF([test "x$MVN" = "x"], [
   AC_CHECK_TOOL([MVN], [mvn], [no])