don't build phpdbg by default

[tvlooy]

When compiling readline as shared extension for the cli SAPI, this failed because phpdbg is compiled by default and needs readline. Compiling with or without readline works, only compiling as shared extension makes phpdbg fail.

/usr/src/php/php-src/sapi/phpdbg/phpdbg_cmd.c:765: undefined reference to `readline'
/usr/src/php/php-src/sapi/phpdbg/phpdbg_cmd.c:773: undefined reference to `add_history'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
*** Error 1 in /usr/src/php/php-src (Makefile:293 'sapi/phpdbg/phpdbg')

I don't know why phpdbg is compiled by default. Maybe this was commited by mistake in 378a05f0de7#diff-70ffcc68633eb9f00e5f1aea6023fcdeR6

This PR suggests to turn it off again. Or, maybe we should leave it on by default and need a --disable-phpdbg instead?

[nikic]

/cc @bwoebi as you enabled it by default.

If we do this, --enable-phpdbg needs to be added to the CI configures.

Regardless of whether or not phpdbg is enabled by default, that readline issue looks like a problem that has to be fixed independently.

[tvlooy]

@nikic travis/compile.sh already has a --enable-phpdbg

[carusogabriel]

@tvlooy @bwoebi What's the status here?

[tvlooy]

still relevant. phpdbg is being compiled by default, this PR stops that behavior

The fact that you need readline compiled in when you build with phpdbg is something I personally don't have problems with. I guess that even makes sense

[krakjoe]

The original problem, which is the shared build making phpdbg build fail, is not so easy to fix. SAPI's are configured before extensions, so at configure time for phpdbg, readline is not configured, therefore we cannot detect whether it is shared or static.

EDIT: I found a way ...

[krakjoe]

Fixed in 7af270e

By default readline/phpdbg integration is enabled, and assumes a static build as it does now - this configuration will still fail, as it does now.

To have the build pass with shared readline you must --disable-phpdbg-readline

[tvlooy]

ok thanks @krakjoe

[petk]

Hello, this seems to fail now:

./buildconf && ./configure --disable-all && make

Undefined symbols for architecture x86_64:
  "_add_history", referenced from:
      _phpdbg_read_input in phpdbg_cmd.o
  "_readline", referenced from:
      _phpdbg_read_input in phpdbg_cmd.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Makefile:273: sapi/phpdbg/phpdbg] Error 1

[krakjoe]

Fixed in b7442f1

Now readline support is disabled by default in phpdbg, enabled it when building readline static with --enable-phpdbg-readline ...