[gettext]Support Linux and OSX build

[JackBoosY]

• Support Linux Build
• Support OSX Build
• Modify dependencies
• test

[JackBoosY]

@Neumann-A @voskrese Could you test it?
I don't think these files generated now is complete.

[past-due]

I'm not sure this approach is ideal? There is already a config.unix.h.in, and code in the CMakeLists.txt to handle macOS / Linux builds. (Admittedly, it may need a little bit of tweaking for Linux, although a while ago I tested it on Ubuntu.)

Also, using vcpkg_configure_make builds for macOS (at least) is going to be problematic, as the gettext runtime's native configure / build scripts do various undesirable things, like trigger a messagebox to install a Java runtime (even if --disable-java is specified - this may depend on the version of macOS). I'd strongly encourage sticking with the current CMakeLists.txt setup for the port for macOS.

[JackBoosY]

@past-due Infact, if you need to use gettext in Linux and OSX, it is actually installed using apt / yum / brew instead of using gettext in vcpkg.
See code here:

vcpkg/ports/gettext/portfile.cmake

Line 7 in 5c415ff

return()

So that's why I create this PR.

[past-due]

@JackBoosY: Ah, to clarify: A little while back, I tested the gettext port with that

if(VCPKG_TARGET_IS_LINUX)
    set(VCPKG_POLICY_EMPTY_PACKAGE enabled)
    ...
    return()

block removed / commented-out, and it built on Ubuntu.

For reference: #4849

Also that block does not apply to macOS builds, which use the config.unix.h.in and logic in the CMakeLists.txt today. (I use these quite frequently, and actually fixed those macOS builds back in #4849.)

Have you tried simply commenting out the VCPKG_POLICY_EMPTY_PACKAGE block that applies to Linux? It's possible something broke since #4849, but it was working with the CMake build setup in that case.

[JackBoosY]

@past-due I will have a try, thanks for the info.

[JackBoosY]

/azp run

[azure-pipelines]

Azure Pipelines failed to run 1 pipeline(s).

[JackBoosY]

Replaced by #11776