As of 742dcba `go build` can accept
`$CC` with spaces and quotes, which lets us easily use `zig cc` as the C
compiler, or easily pass extra compiler parameters:

```
CC="zig cc" go build <...>
CC="clang-13 -v" go build <...>
CC="zig cc -Wl,--print-gc-sections" go build <...>
```

However, the same does not apply for building go itself:

```
$ CC="zig cc" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
go tool dist: cannot invoke C compiler "zig cc": exec: "zig cc": executable file not found in $PATH

Go needs a system C compiler for use with cgo.
To set a C compiler, set CC=the-compiler.
To disable cgo, set CGO_ENABLED=0.
```

With this change Go can be built directly with `zig cc`:

```
CC="zig cc -Wl,--no-gc-sections" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
Building Go toolchain1 using /usr/local/go.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
<...>
```

Fixes golang#52990

As of 742dcba `go build` can accept
`$CC` with spaces and quotes, which lets us easily use `zig cc` as the C
compiler, or easily pass extra compiler parameters:

```
CC="zig cc" go build <...>
CC="clang-13 -v" go build <...>
CC="zig cc -Wl,--print-gc-sections" go build <...>
```

However, the same does not apply for building go itself:

```
$ CC="zig cc" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
go tool dist: cannot invoke C compiler "zig cc": exec: "zig cc": executable file not found in $PATH

Go needs a system C compiler for use with cgo.
To set a C compiler, set CC=the-compiler.
To disable cgo, set CGO_ENABLED=0.
```

With this change Go can be built directly with `zig cc` (the linker arg
will disappear with golang#52815 and/or golang#52690):

```
$ CC="zig cc -Wl,--no-gc-sections" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
Building Go toolchain1 using /usr/local/go.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
Building Go toolchain3 using go_bootstrap and Go toolchain2.
Building packages and commands for linux/amd64.
---
Installed Go for linux/amd64 in /home/motiejus/code/go
Installed commands in /home/motiejus/code/go/bin
$ ../bin/go version
go version devel go1.19-811f1913a8 Thu May 19 09:44:49 2022 +0300 linux/amd64
```

Fixes golang#52990

As of CL 334732 `go build` can accept `$CC` with spaces and quotes,
which lets us easily use `zig cc` as the C compiler, or easily pass
extra compiler parameters:

```
CC="zig cc" go build <...>
CC="clang-13 -v" go build <...>
CC="zig cc -Wl,--print-gc-sections" go build <...>
```

However, the same does not apply for building go itself:

```
$ CC="zig cc" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
go tool dist: cannot invoke C compiler "zig cc": exec: "zig cc": executable file not found in $PATH

Go needs a system C compiler for use with cgo.
To set a C compiler, set CC=the-compiler.
To disable cgo, set CGO_ENABLED=0.
```

With this change Go can be built directly with `zig cc` (the linker arg
will disappear with golang#52815 and/or golang#52690):

```
$ CC="zig cc -Wl,--no-gc-sections" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
Building Go toolchain1 using /usr/local/go.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
Building Go toolchain3 using go_bootstrap and Go toolchain2.
Building packages and commands for linux/amd64.
---
Installed Go for linux/amd64 in /home/motiejus/code/go
Installed commands in /home/motiejus/code/go/bin
$ ../bin/go version
go version devel go1.19-811f1913a8 Thu May 19 09:44:49 2022 +0300 linux/amd64
```

Fixes golang#52990

As of CL 334732 `go build` can accept `$CC` with spaces and quotes,
which lets us easily use `zig cc` as the C compiler, or easily pass
extra compiler parameters:

```
CC="zig cc" go build <...>
CC="clang-13 -v" go build <...>
CC="zig cc -Wl,--print-gc-sections" go build <...>
```

However, the same does not apply for building go itself:

```
$ CC="zig cc" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
go tool dist: cannot invoke C compiler "zig cc": exec: "zig cc": executable file not found in $PATH

Go needs a system C compiler for use with cgo.
To set a C compiler, set CC=the-compiler.
To disable cgo, set CGO_ENABLED=0.
```

With this change Go can be built directly with `zig cc` (the linker arg
will disappear with CL 407216):

```
$ CC="zig cc -Wl,--no-gc-sections" ./make.bash
Building Go cmd/dist using /usr/local/go. (go1.18.2 linux/amd64)
Building Go toolchain1 using /usr/local/go.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
Building Go toolchain3 using go_bootstrap and Go toolchain2.
Building packages and commands for linux/amd64.
---
Installed Go for linux/amd64 in /home/motiejus/code/go
Installed commands in /home/motiejus/code/go/bin
$ ../bin/go version
go version devel go1.19-811f1913a8 Thu May 19 09:44:49 2022 +0300 linux/amd64
```

Fixes golang#52990