Enable compiling extensions statically into PHP

[jjeising]

This should enable compiling both extensions statically into PHP and fixes #894. I've tested building statically and as a shared module against PHP 7.2.13.

I've tried to introduce only a few extraneous changes. I've removed some duplicate lines from php_sqlsrv(_int).h that were already present in core_sqlsrv.h. For a short time I also had this change included, but is not needed, as the ini definitions will remain in the internal header files. You may be nonetheless interested in cleaning this up a little.

To include both extensions at the same time on Windows there is probably a change needed to configure_module_dirname + "\\shared" in config.w32, but I'm not familiar with syntax there.

[coveralls]

Coverage increased (+0.02%) to 72.342% when pulling 579ac0a on jjeising:php-static-build into d4f840f on Microsoft:dev.

[codecov-io]

Codecov Report

Merging #904 into dev will increase coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev     #904      +/-   ##
==========================================
+ Coverage   80.32%   80.37%   +0.05%     
==========================================
  Files          25       25              
  Lines        7731     7731              
==========================================
+ Hits         6210     6214       +4     
+ Misses       1521     1517       -4

Impacted Files	Coverage Δ
...x86/php-7.1.25-src/ext/sqlsrv/shared/core_init.cpp	54.16% <0%> (-4.33%)	⬇️
...php-7.1.25-src/ext/pdo_sqlsrv/shared/core_init.cpp	54.16% <0%> (-4.33%)	⬇️
...php-7.1.25-src/ext/pdo_sqlsrv/shared/core_stmt.cpp	75.64% <0%> (-0.1%)	⬇️
...4/x86/php-7.1.25-src/ext/pdo_sqlsrv/pdo_parser.cpp	91.35% <0%> (ø)	⬆️
...phpdev/vc14/x86/php-7.1.25-src/ext/sqlsrv/stmt.cpp	88.99% <0%> (ø)	⬆️
...phpdev/vc14/x86/php-7.1.25-src/ext/sqlsrv/util.cpp	84.37% <0%> (ø)	⬆️
...c14/x86/php-7.1.25-src/ext/pdo_sqlsrv/pdo_stmt.cpp	85.07% <0%> (ø)	⬆️
...phpdev/vc14/x86/php-7.1.25-src/ext/sqlsrv/conn.cpp	83.88% <0%> (ø)	⬆️
...c14/x86/php-7.1.25-src/ext/pdo_sqlsrv/pdo_util.cpp	90.21% <0%> (ø)	⬆️
...vc14/x86/php-7.1.25-src/ext/pdo_sqlsrv/pdo_dbh.cpp	91.68% <0%> (ø)	⬆️
... and 7 more

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[david-puglielli]

This change makes it impossible to compile just pdo_sqlsrv without sqlsrv (I get a bunch of undefined reference compilation errors), but without it I get multiple definition errors if I try to compile both drivers because the core source files are included twice. This is one of the reasons why we never added the ability to compile the drivers statically. Do you know a way around these errors?

[jjeising]

This change makes it impossible to compile just pdo_sqlsrv without sqlsrv (I get a bunch of undefined reference compilation errors)

Can you elaborate a bit what you've tried to do? This should only happen if you copy both extensions to the PHP source ext/ directory and then specify --disable-sqlsrv. As this should be required rarely I thought it might be better than no support. But it is probably possible to test if sqlsrv is enabled, like this. I'll have a look.

[jjeising]

@david-puglielli I've added the additional check. Had to swap between the extensions, because pdo_sqlsrv is included first by buildconf. This might be a bit fragile, but enables me to build both without arguments and with --with-pdo_sqlsrv --disable-sqlsrv and also with both extensions active. Does this address your concerns?

[david-puglielli]

Ok, I think your recent changes address my concerns. I've tested every combination, and the only one that doesn't work is pdo_sqlsrv shared and sqlsrv static, but I don't think that's a big problem. We will continue testing and see if we can get it working on Windows as well.

[david-puglielli]

We will be merging this PR as soon as we figure out how to implement this on Windows as well, but we can't before then. Please feel free to update this PR if you have any suggestions.

[david-puglielli]

Ok, figured out how to get it working on Windows. Changes were required to config.w32 for sqlsrv, but we also had to move DllMain out of the core files and put a separate copy in init.cpp and pdo_init.cpp. Additionally we had to add an extern declaration in php_pdo_sqlsrv_int.cpp.

@jjeising Please see my changes at the static-compilation branch of david-puglielli/msphpsql and incorporate them in this PR.

[jjeising]

Thanks for your additional work! 🎉

Please see my changes at the static-compilation branch of david-puglielli/msphpsql and incorporate them in this PR.

I've squashed the missing extern declaration and updated config.w32. I've tried to reduce duplicate code there.