Bug#1062799: glslang-dev: Missing libraries listed in glslang.pc -- fixed.

[Philippe SWARTVAGHER]

Hello,

I realized this bug prevents shaderc from migrating to testing.

Please have a look on my MR
(https://salsa.debian.org/xorg-team/vulkan/glslang/-/merge_requests/6),
which (among other things) fixes this bug.

Thanks,

Philippe.