This switches to using the CMake FetchContent path to dynamically download
and build PCRE2, allowing us to drop the vendored sources.
The FISH_USE_SYSTEM_PCRE2 CMake option is kept, but if false it now means
fetch-and-build PCRE2 rather than building vendored sources.
Note FetchContent was introduced in CMake 3.11. That is now a prerequisite
for building fish with FISH_USE_SYSTEM_PCRE2 disabled.
The CMake variable FISH_USE_SYSTEM_PCRE2 now controls whether fish uses
system PCRE2 or the bundled version. The default is to use the system
version, unless no such version is found, or unless it is a macOS build
with code signing. Note the default behavior has not changed.
Fixes#6952
This commit updates PCRE2 to 10.34, and we no longer include what's in their
tarball as-is. I've yanked out a lot of uneccessary stuff for the sake of the
size of our codebase.
original pcre2-10.34 dir: 11.5MB
pcre2 dir in this commit: 1.6MB
* Remove documentation, makefiles, test suites, etc. LICENSE remains.
* Disable building tests when configuring PCRE2
* Yard out JIT support: delete src/jit, src/pcre2_jit_*.c, and code doing
stuff to code->executable_jit that needs a jit header (it was already NULL
because we've always built with JIT disabled).
* Remove most .c and .h files not needed to compile: pcre2grep code,
pcre2test code, dftables.c, pcre2_printint.c, pcre2_fuzzsupport.c ...
* Remove FindBZip2, FindZLIB, FindReadline, FindEditline. These were used
only by pcre2grep and made CMake's report misleading with regard to
optional packages being used.
* Remove configure.ac except for version number and date which CMake checks
Next time we update PCRE2, refer to this commit message as well as a diff
between pcre2-10.34.tar.gz and ./pcre2-10.34/. Or better yet, cease including
pcre2.
