Redirect output when searching for archiver

[awvwgk]

Requires some shuffling of routines to avoid dependency cycles.

Fixes #456

[LKedward]

Looks good to me, thanks! 👍

[ghost]

Thanks @awvwgk, it works great in my default environment. However, when I switch to the Intel oneAPI environment, remove GCC toolchain from the PATH and run fpm build --compiler ifort, it displays the message "ar is not recognized as an internal or external command, operable program or batch file." After that, the build continues and ends successfully.

C:\Temp\test5>fpm build --compiler ifort
 + mkdir build\dependencies
'ar' is not recognized as an internal or external command, operable program or batch file.
 + mkdir build\ifort_782887A201FCE169\test5
 + ifort -c test\check.f90 /warn:all /check:all …

[awvwgk]

@brocolis should be fixed now.

[ghost]

I've tested the patch in 3 environments, they all work well, thanks @awvwgk 👍

Toolchain available on PATH	fpm test --compiler gfortran	fpm test --compiler ifort	fpm test --compiler ifx
MinGW	✅	-	-
oneAPI	-	✅	✅
oneAPI + MinGW	✅	✅	✅

In environments (1) and (3), fpm executes ar, while in environment (2), fpm executes lib. I think the use of ar in (3) is a bit inconsistent but it does not cause harm so far and can be resolved later.

[ghost]

In scenario (4), MinGW is found on PATH before Intel oneAPI. It's unusual but it works also.

Toolchain available on PATH	fpm test --compiler gfortran	fpm test --compiler ifort	fpm test --compiler ifx
MinGW	✅	-	-
oneAPI	-	✅	✅
oneAPI + MinGW	✅	✅	✅
MinGW + oneAPI	✅	✅	✅

[LKedward]

Thanks for the thorough testing @brocolis! With that I'll now merge