Replace `CMAKE_SOURCE_DIR` and `CMAKE_BUILD_DIR` with different variables,
or in some cases just remove them.
For some function arguments, prepended `CMAKE_SOURCE_DIR` was removed without
replacement. This includes:
* Sources for `add_library` and `add_executable` (`ZIG_CPP_SOURCES` and `ZIG_WASM2C_SOURCES`)
* Inputs for `configure_file` and `target_include_directory`
* For arguments above, CMake already prepends
`CMAKE_CURRENT_SOURCE_DIR` to them by default, if they are relative paths.
Additionaly, it was removed from arguments of commands that have `WORKING_DIRECTORY` set to
`PROJECT_SOURCE_DIR`, they will be similarly converted by CMake for us.
Also:
* Move project declaration to the top so that these variables are
available earlier.
* Avoid calling "git" executable if ".git" directory does not exist.
* Swap "--prefix" and `ZIG_BUILD_ARGS` arguments in cmake/install.cmake
to match same "zig2 build" command in CMakeLists.txt and allow
overriding "--prefix" argument
Signed-off-by: Eric Joldasov <bratishkaerik@landless-city.net>
build.zig: add a 'compile' step to compile the self-hosted compiler
without installing it.
Compilation: set cache mode to whole when using the LLVM backend and
--enable-cache is passed.
This makes `zig build` act the same as it does with stage1. Upside is
that a second invocation of `zig build` on an unmodified source tree
will avoid redoing the compilation again. Downside is that it will
proliferate more garbage in the project-local cache (same as stage1).
This can eventually be fixed when Zig's incremental compilation is more
robust; we can go back to having LLVM use CacheMode.incremental and rely
on it detecting no changes and avoiding doing the flush() step.
This is a simplification of the cmake build script which introduces a
new "stage3" target that is built by default, which builds and installs
a stage3 zig.
It greatly simplifies the build instructions for Zig, making it conform
to the regular cmake routine, while still producing a stage3 artifact.
Rather than `zig0 build ...` the build now does
`zig0 build-lib ...`, avoiding the requirement of linking the build
script, and thus avoiding the requirement of finding native libc,
for systems where libc is the system ABI.