Re: PCRE v2 compile error, was Re: What's cooking in git.git (May 2017, #01; Mon, 1)

> On 05/02, Ævar Arnfjörð Bjarmason wrote:
>> On Tue, May 2, 2017 at 2:09 PM, Johannes Schindelin
>> <Johannes.Schindelin@gmx.de> wrote:
>> > Hi Ævar,
>> >
>> > On Sun, 30 Apr 2017, Junio C Hamano wrote:
>> >
>> >> * ab/grep-pcre-v2 (2017-04-25) 20 commits
>> >>  - SQUASH???
>> >>  - Makefile & configure: make PCRE v2 the default PCRE implementation
>> >>  - grep: remove support for concurrent use of both PCRE v1 & v2
>> >>  - grep: add support for PCRE v2
>> >>  - grep: add support for the PCRE v1 JIT API
>> >>  - perf: add a performance comparison test of grep -E and -P
>> >>  - grep: change the internal PCRE code & header names to be PCRE1
>> >>  - grep: change the internal PCRE macro names to be PCRE1
>> >>  - test-lib: rename the LIBPCRE prerequisite to PCRE
>> >>  - grep: make grep.patternType=[pcre|pcre1] a synonym for "perl"
>> >>  - grep & rev-list doc: stop promising libpcre for --perl-regexp
>> >>  - log: add -P as a synonym for --perl-regexp
>> >>  - log: add exhaustive tests for pattern style options & config
>> >>  - grep: add a test for backreferences in PCRE patterns
>> >>  - Makefile & configure: reword outdated comment about PCRE
>> >>  - grep: remove redundant `regflags &= ~REG_EXTENDED` assignments
>> >>  - grep: remove redundant regflags assignment under PCRE
>> >>  - grep: submodule-related case statements should die if new fields are added
>> >>  - grep: add tests for grep pattern types being passed to submodules
>> >>  - grep: amend submodule recursion test in preparation for rx engine testing
>> >>
>> >>  PCRE2, which has an API different from and incompatible with PCRE,
>> >>  can now be chosen to support "grep -P -e '<pattern>'" and friends.
>> >
>> > FWIW for quite a couple of recent builds, `pu` fails on Windows with a
>> > variation of this error:
>> >
>> >             CC blob.o
>> >         In file included from revision.h:5:0,
>> >                          from bisect.c:4:
>> >         grep.h:16:19: fatal error: pcre2.h: No such file or directory
>> >          #include <pcre2.h>
>> >                            ^
>> >         compilation terminated.
>> >
>> > Maybe this can be fixed before hitting `next`?
>>
>> This will be due to a combination of the build machine not having pcre
>> v2 (but having v1) & my "Makefile & configure: make PCRE v2 the
>> default PCRE implementation" patch, which makes v2 the default for
>> USE_LIBPCRE=YesPlease.
>>
>> Is it easy to install v2 on these build machines? Alternatively that
>> patch could be ejected out of pu, or you could USE_LIBPCRE1=YesPlease
>> to use v1, but as explained in that commit I think it makes sense to
>> make v2 the default.
>
> Shouldn't the Makefile check for the existence of PCREv2 before making
> it the default?