| Subject: | c_source is compiled even if --pureperl-only is set |
Currently, even if --pureperl-only is set, c_source is compiled.
An example is here: https://github.com/skaji/perl-mb-issue
```
$ perl Build.PL --pureperl-only
Created MYMETA.yml and MYMETA.json
Creating new 'Build' script for 'Foo' version '0.001'
$ ./Build
Building Foo
cc -Isrc -I/Users/skaji/env/plenv/versions/01.18-v5.25.8-272/lib/perl5/5.25.9/darwin-2level/CORE -c -fno-common -DPERL_DARWIN -mmacosx-version-min=10.12 -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -DPERL_USE_SAFE_PUTENV -O3 -g -o src/add.o src/add.c
```
I think the following patch solves this issue.
```
diff --git lib/Module/Build/Base.pm lib/Module/Build/Base.pm
index 26735da..baa37b0 100644
--- lib/Module/Build/Base.pm
+++ lib/Module/Build/Base.pm
@@ -2859,6 +2859,7 @@ sub process_support_files {
my $self = shift;
my $p = $self->{properties};
return unless $p->{c_source};
+ return if $self->pureperl_only && $self->allow_pureperl;
my $files;
if (ref($p->{c_source}) eq "ARRAY") {
```