make: Allow OTP to be built deterministically

Add a --enable-deterministic-build to the configure script,
which sets ERL_DETERMINISTIC=yes throughout the relevant
Makefiles, which then invoke the relevant build stages with the
+deterministic option.

This addresses absolute paths being included in generated .erl files
and compiled .beam files that resulted in builds from different source
directories generating different artefacts (which is a component of the
issue in erlang#4482).

I think it would make sense to make this the default at some stage, but
I've put the change behind a flag for now to decouple
making deterministic OTP builds possible from making them the default.

Having +deterministic set results in compiler options being
removed from the module info for modules where this options was used.
This may have other implications for users of OTP.

For tests themselves, +determinism is not set, since many test cases
depend on accessing the test module's compilation options, or other
features not available in deterministic mode, in order to configure
themselves. For tests of the determinism feature specifically,
+deterministic must be explicitly passed to the compiler within the
relevant test cases.

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/eunit/test/Makefile b/lib/eunit/test/Makefile
index e2fbdf7241..1bd9c0a07c 100644
--- a/lib/eunit/test/Makefile
+++ b/lib/eunit/test/Makefile
@@ -45,6 +45,7 @@ RELSYSDIR = $(RELEASE_PATH)/eunit_test
 # ----------------------------------------------------
 ERL_MAKE_FLAGS +=
 ERL_COMPILE_FLAGS +=
+ERL_COMPILE_FLAGS := $(filter-out +deterministic,$(ERL_COMPILE_FLAGS))
 
 EBIN = .