[erlang] Run tests even if rebar3 is absent

Summary:
Erlang tests used to be rebar3 projects but have long been moved to use
`erlc` directly. Thus, they should be enabled if `erlc` is available on
the machine (not it if `rebar3` is available on the machine).

Reviewed By: jvillard

Differential Revision: D45736354

fbshipit-source-id: 6620fc911e033455434005bea26db2c9a51aecfd

Makefile

@@ -164,14 +164,18 @@ endif # HAS_OBJC
 endif # BUILD_C_ANALYZERS
 
 ifeq ($(BUILD_ERLANG_ANALYZERS),yes)
-ifneq ($(REBAR3),no)
+ifneq ($(ERLC),no)
+ifneq ($(ESCRIPT),no)
 DIRECT_TESTS += \
   erlang_pulse \
   erlang_pulse-otp \
   erlang_pulse-taint \
   erlang_topl \
   erlang_compiler \
 
+endif
+endif
+ifneq ($(REBAR3),no)
 BUILD_SYSTEMS_TESTS += rebar3
 endif
 endif # BUILD_ERLANG_ANALYZERS

Makefile.autoconf.in

@@ -32,6 +32,8 @@ DIFF_CAN_FORMAT := @DIFF_CAN_FORMAT@
 EMACS := @EMACS@
 ENABLE_OCAMLOPT_CUSTOM_CC := @ENABLE_OCAMLOPT_CUSTOM_CC@
 ENABLE_OCAML_BINANNOT := @ENABLE_OCAML_BINANNOT@
+ERLC := @ERLC@
+ESCRIPT := @ESCRIPT@
 exec_prefix = @exec_prefix@
 GNU_SED := @GNU_SED@
 HACKC := @HACKC@

configure.ac

@@ -331,6 +331,7 @@ AC_SUBST([OPAMSWITCH])
 
 if test "x$enable_erlang_analyzers" = "xyes"; then
   AC_CHECK_TOOL([ESCRIPT], [escript], [no])
+  AC_CHECK_TOOL([ERLC], [erlc], [no])
   AC_CHECK_TOOL([REBAR3], [rebar3], [no])
 fi
 # end if($enable_erlang_analyzers)