Meson failed to archive shared libraries in AIX.

[KamathForAIX]

Describe the bug
Meson with ninja >= 1.12 failed to archive shared libraries in AIX.

To Reproduce
Build any library like glib2 which creates shared libraries that share symbols amongst themselves.

Expected behavior
A clean build

system parameters

• Is this a cross build or just a plain native build (for the same computer)? No
• what operating system (e.g. MacOS Catalina, Windows 10, CentOS 8.0, Ubuntu 18.04, etc.) AIX
• what Python version are you using e.g. 3.8.0 Python3.9
• what meson --version Master branch
• what ninja --version if it's a Ninja build - 1.12 and higher

So as reported here by an AIX user, meson does not archive with ninja >= 1.12.

The reason being I missed out marking SHSYM here target file to be the archive during the shared library archive feature development for AIX.

What this does is tell Ninja that "you need to build the archive first and then depend on that to build the next shared library archive.".

If we do not do that, then though Ninja wants to link the archive, it will skip creating the archive since in SHSYM it sees just a ".so" and not the archive. Hence, when multiple threads execute, we do not have the archive, and we get the build error like how the user got here.

One sample example for a wrong build.ninja file is this,

build glib/libglib-2.0.so.0.p/libglib-2.0.so.0.symbols: SHSYM glib/libglib-2.0.so.0
 IMPLIB = glib/libglib-2.0.a

The SHSYM glib/libglib-2.0.so.0 part is the problem. I want to change this to an archive, and this will fix the issue.

cc @eli-schwartz

Kindly let me know what you think.