Change libzerocash include paths to be "standard" / friendly w/ ./depends.

[nathan-at-least]

Currently building apps against an installed libzerocash requires passing a special -I flag. This is because the include paths it uses internally are not relative to the current file, nor are they the "standard installed paths", but something in between. Building it directly works only because it hardcodes -I . in the Makefile.

An example is the include in ./libzerocash/Zerocash.h line 69 which is:

 #include "libzerocash/utils/util.h"

A relative include wouln't require a custom -I and would be:

#include "utils/util.h"

-whereas the "system" include path would be:

#include <libzerocash/libzerocash/utils/util.h>

-based on the current installation layout.

[nathan-at-least]

Here is the most important motivator for us: 65db228#commitcomment-13651461

Non-standard include paths breaks autoconf macros, so we resort to brittle work-arounds.

[defuse]

Another thing we might want to do is enable passing of additional CFLAGS into the makefile. This way we keep track of which flags are "package default flags" and which flags are "things we needed to add to make it work with bitcoind." Here's one example of us having to duplicate all of the default flags:

dd5c000#diff-f752a316bb10ad5a562e83238800a5bcR24

[nathan-at-least]

+1

I believe the autotools convention is that there are a set of "user"
variables that the person running "make" should always be able to
customize, eg: make CXXFLAGS='-I/wacky/bananas -O42'

Here's a description of that convention
https://www.gnu.org/software/automake/manual/html_node/User-Variables.html

From our experience with libsnark and libzerocash as dependencies, I now
finally understand the need for this convention. Since they use
hand-written Makefiles, I think we can implement this by:

a. renaming user variables like CXXFLAGS to COMPLETE_CXXFLAGS, and
defining somewhere COMPLETE_CXXFLAGS = $(PACKAGE_CXXFLAGS) $(CXXFLAGS). (I'm not actually sure if we need the user variable to come
first or last. :-/
b. find all cases where the user variables are used implicitly, then make
them explicit so they refer to $(COMPLETE_<blah>) instead of the
implicit $(<blah>).

Hm... now I'm slowly having my mind warped by the dark side of the force
and wondering if switching the build system to autotools is the easier path.

On Thu, Oct 8, 2015 at 1:46 PM, Taylor Hornby notifications@github.com
wrote:

Another thing we might want to do is enable passing of additional CFLAGS
into the makefile. This way we keep track of which flags are "package
default flags" and which flags are "things we needed to add to make it work
with bitcoind." Here's one example of us having to duplicate all of the
default flags:

dd5c000#diff-f752a316bb10ad5a562e83238800a5bcR24
dd5c000#diff-f752a316bb10ad5a562e83238800a5bcR24

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Nathan Wilcox
Least Authoritarian

email: nathan@leastauthority.com
twitter: @least_nathan

[ebfull]

I'm not sure that this is a problem anymore.

[nuttycom]

libzerocash no longer exists.