icecat: add + fix remove-rustc-check.patch

srcpkgs/icecat/patches/remove-rustc-check.patch

@@ -0,0 +1,41 @@
+Mozilla rustc check does not support crossbuild: let's remove it
+Remove calls to unwrap_rustup, they fail if rustup isn't present
+
+--- build/moz.configure/rust.configure	2019-07-06 03:48:30.000000000 +0200
++++ build/moz.configure/rust.configure	2019-07-09 22:35:23.326851798 +0200
+@@ -79,9 +79,6 @@
+ 
+     return unwrap
+ 
+-rustc = unwrap_rustup(rustc, 'rustc')
+-cargo = unwrap_rustup(cargo, 'cargo')
+-
+ 
+ set_config('CARGO', cargo)
+ set_config('RUSTC', rustc)
+@@ -366,25 +363,6 @@
+             os.write(in_fd, source)
+             os.close(in_fd)
+ 
+-            cmd = [
+-                rustc,
+-                '--crate-type', 'staticlib',
+-                target_arg,
+-                '-o', out_path,
+-                in_path,
+-            ]
+-
+-            def failed():
+-                die(dedent('''\
+-                Cannot compile for {} with {}
+-                The target may be unsupported, or you may not have
+-                a rust std library for that target installed. Try:
+-
+-                  rustup target add {}
+-                '''.format(host_or_target.alias, rustc, rustc_target)))
+-            check_cmd_output(*cmd, onerror=failed)
+-            if not os.path.exists(out_path) or os.path.getsize(out_path) == 0:
+-                failed()
+         finally:
+             os.remove(in_path)
+             os.remove(out_path)