The introduction of setup_env as a global concept caused the rebar_port_compiler
implementation to start getting called a LOT. The expansion of environment variables
that happens in the port compiler was O(n^n), which means you could see upwards of
80k invocations of lists:foldl on a single app "./rebar clean". This commit reworks
the expansion to be O(n^2), and reduces the running time for the same operation by
60%+. On a large project like Riak, the end result is that a build went from 200
seconds to 73.
Calling erlang:system_info(wordsize) yields the internal word size of
the Erlang emulator. But due to the halfword emulator, need to pass
{wordsize, external} instead to get the word size, or pointer size, as
seen by external code such as NIFs. The halfword emulator has 4 byte
internal words but 8 byte external words due to 64-bit compilation,
which means NIFs for the halfword emulator also have to be compiled
64-bit. But just passing wordsize is equivalent to passing {wordsize,
internal}, which does not indicate the pointer size for the halfword
emulator.
Older versions of Erlang do not support {wordsize, external}, though,
so continue to pass just wordsize for those versions.
Change the second parameter of a regex tagged port_source from being a
filename or wildcard to being a list of filenames or wildcards.
Previously: {"R14", "c_src/*.c"}
Now: {"R14", ["c_src/*.c"]}
Motivation for change is to avoid repeating regexes.
The logic changes from strict overrides to a hybrid for merging os_env
and defaults, whereby defaults are chosen if they are not set in the
os_env or if the defaults contains substitutions (at which point os
environment is substituted).
This still means that rebar.config works as it did before, where it
overrides or substitutes based on the use of $VAR, but that default
and os environment merging works such that the common cases of
providing CC or LDFLAGS in the users environment or command line work
as you might expect. In that CC is overriden by the os environment
unless rebar.config overrides it, and LDFLAGS from the user environment
is appended or prepended based on defaults and rebar.config.
Addresses problems with https://github.com/basho/rebar/pull/71
Also keeps the fix for bug 255.
On one project I have a need to specify port_sources on R14 only
and on another different project port_sources for Darwin and Linux.
To this end add support to handle tuples of the form
{ArchRegex, PortSource} in the port_sources list, eg:
{port_sources, [{"R14", ["c_src/*.c"]}]}.
