Enable Meson support

[ssumpf]

Some projects we ported or want to port have migrated to the Meson build system (e.g., Mesa, Qemu, media driver, scrcpy). Therefore, it makes sense to enable Meson support in Goa.

[ssumpf]

85d5686 is a first step to support Meson:

• it supports x86_64 binaries only (no shared libraries) nor arm_v8a
• tested with https://github.com/ssumpf/goa-projects/tree/master/glmark2
• updated documentation
• added hello_meson test
• added hello_meson to test.expect

[jschlatow]

@ssumpf That's a valuable addition to Goa. Please have a look at my (few) inline comments.

[ssumpf]

@jschlatow: c89db8a adds a pkg-config.tcl helper script and outputs the _usedapi status during the setup phase.

[ssumpf]

@jschlatow: I forgot to adjust a comment. Have a look at c859273 instead please.

[jschlatow]

@ssumpf Thanks! I was also thinking about the issue with matching the required library names with the api names. Since there are api archives that produce multiple libraries (e.g. mesa, openssl), I was thinking about looking for lib.so files in var/abi/ instead of parsing the used_apis file. What's your opinion?

No matter what we do, we will only have a heuristic pkg-config emulation. I therefore like your idea about logging the pkg-config requests and printing the status.

[ssumpf]

@ssumpf Thanks! I was also thinking about the issue with matching the required library names with the api names. Since there are api archives that produce multiple libraries (e.g. mesa, openssl), I was thinking about looking for lib.so files in var/abi/ instead of parsing the used_apis file. What's your opinion?

@jschlatow: Sounds more correct, so I will change that.

No matter what we do, we will only have a heuristic pkg-config emulation. I therefore like your idea about logging the pkg-config requests and printing the status.

@jschlatow: True

[ssumpf]

@jschlatow: 17db994 searches for modules in var/abi.

[ssumpf]

@jschlatow: adc537d features the lsearch approach while I opted for an exact pattern.

[jschlatow]

Thanks. I merged your changes as 4b583dc and 2fd5e9b to staging.