Support building x86_64 packages on aarch64-darwin

Thanks to Rosetta 2, we can build x86 packages on aarch64-darwin
machines (although, it's not perfect).

This adds a new configuration option -- `additional_build_systems` --
which will cause the builder to spawn additional async tasks for each
additional build system.

Cargo.lock

@@ -85,39 +85,45 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "23b62fc65de8e4e7f52534fb52b0f3ed04746ae267519eef2a83941e8085068b"
 
 [[package]]
-name = "async-std"
+name = "async-channel"
-version = "1.5.0"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "538ecb01eb64eecd772087e5b6f7540cbc917f047727339a472dafed2185b267"
+checksum = "2114d64672151c0c5eaa5e131ec84a74f06e1e559830dabba01ca30605d66319"
 dependencies = [
- "async-task 1.3.1",
+ "concurrent-queue",
- "crossbeam-channel 0.4.4",
+ "event-listener",
- "crossbeam-deque",
+ "futures-core",
+]
+
+[[package]]
+name = "async-std"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a45cee2749d880d7066e328a7e161c7470ced883b2fd000ca4643e9f1dd5083a"
+dependencies = [
+ "async-task 3.0.0",
  "crossbeam-utils 0.7.2",
+ "futures-channel",
  "futures-core",
  "futures-io",
  "futures-timer",
  "kv-log-macro",
  "log 0.4.14",
  "memchr",
- "mio 0.6.23",
- "mio-uds",
  "num_cpus",
  "once_cell",
  "pin-project-lite 0.1.12",
  "pin-utils",
  "slab",
+ "smol",
+ "wasm-bindgen-futures",
 ]
 
 [[package]]
 name = "async-task"
-version = "1.3.1"
+version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ac2c016b079e771204030951c366db398864f5026f84a44dafb0ff20f02085d"
+checksum = "c17772156ef2829aadc587461c7753af20b7e8db1529bc66855add962a3b35d3"
-dependencies = [
- "libc",
- "winapi 0.3.9",
-]
 
 [[package]]
 name = "async-task"
@@ -125,6 +131,12 @@ version = "4.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e91831deabf0d6d7ec49552e489aed63b7456a7a3c46cff62adad428110b0af0"
 
+[[package]]
+name = "atomic-waker"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "065374052e7df7ee4047b1160cca5e1467a12351a40b3da123c870ba0b8eda2a"
+
 [[package]]
 name = "autocfg"
 version = "1.0.1"
@@ -189,12 +201,38 @@ dependencies = [
  "wyz",
 ]
 
+[[package]]
+name = "blocking"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2468ff7bf85066b4a3678fede6fe66db31846d753ff0adfbfab2c6a6e81612b"
+dependencies = [
+ "async-channel",
+ "atomic-waker",
+ "futures-lite",
+ "once_cell",
+ "parking 1.0.6",
+ "waker-fn",
+]
+
+[[package]]
+name = "bumpalo"
+version = "3.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4a45a46ab1f2412e53d3a0ade76ffad2025804294569aae387231a0cd6e0899"
+
 [[package]]
 name = "byteorder"
 version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
 
+[[package]]
+name = "cache-padded"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1db59621ec70f09c5e9b597b220c7a2b43611f4710dc03ceb8748637775692c"
+
 [[package]]
 name = "cc"
 version = "1.0.68"
@@ -226,6 +264,15 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "concurrent-queue"
+version = "1.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "30ed07550be01594c6026cff2a1d7fe9c8f683caa798e12b68694ac9e88286a3"
+dependencies = [
+ "cache-padded",
+]
+
 [[package]]
 name = "cookie-factory"
 version = "0.3.2"
@@ -248,16 +295,6 @@ version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ea221b5284a47e40033bf9b66f35f984ec0ea2931eb03505246cd27a963f981b"
 
-[[package]]
-name = "crossbeam-channel"
-version = "0.4.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b153fe7cbef478c567df0f972e02e6d736db11affe43dfc9c56a9374d1adfb87"
-dependencies = [
- "crossbeam-utils 0.7.2",
- "maybe-uninit",
-]
-
 [[package]]
 name = "crossbeam-channel"
 version = "0.5.1"
@@ -268,32 +305,6 @@ dependencies = [
  "crossbeam-utils 0.8.5",
 ]
 
-[[package]]
-name = "crossbeam-deque"
-version = "0.7.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9f02af974daeee82218205558e51ec8768b48cf524bd01d550abe5573a608285"
-dependencies = [
- "crossbeam-epoch",
- "crossbeam-utils 0.7.2",
- "maybe-uninit",
-]
-
-[[package]]
-name = "crossbeam-epoch"
-version = "0.8.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "058ed274caafc1f60c4997b5fc07bf7dc7cca454af7c6e81edffe5f33f70dace"
-dependencies = [
- "autocfg",
- "cfg-if 0.1.10",
- "crossbeam-utils 0.7.2",
- "lazy_static",
- "maybe-uninit",
- "memoffset",
- "scopeguard",
-]
-
 [[package]]
 name = "crossbeam-utils"
 version = "0.7.2"
@@ -346,6 +357,21 @@ dependencies = [
  "backtrace",
 ]
 
+[[package]]
+name = "event-listener"
+version = "2.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77f3309417938f28bf8228fcff79a4a37103981e3e186d2ccd19c74b38f4eb71"
+
+[[package]]
+name = "fastrand"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3fcf0cee53519c866c09b5de1f6c56ff9d647101f81c1964fa632e148896cdf"
+dependencies = [
+ "instant",
+]
+
 [[package]]
 name = "foreign-types"
 version = "0.3.2"
@@ -399,22 +425,6 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
 
-[[package]]
-name = "fuchsia-zircon"
-version = "0.3.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
-dependencies = [
- "bitflags",
- "fuchsia-zircon-sys",
-]
-
-[[package]]
-name = "fuchsia-zircon-sys"
-version = "0.3.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
-
 [[package]]
 name = "funty"
 version = "1.1.0"
@@ -422,22 +432,83 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fed34cd105917e91daa4da6b3728c47b068749d6a62c59811f06ed2ac71d9da7"
 
 [[package]]
-name = "futures-core"
+name = "futures-channel"
 version = "0.3.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0402f765d8a89a26043b889b26ce3c4679d268fa6bb22cd7c6aad98340e179d1"
+checksum = "e682a68b29a882df0545c143dc3646daefe80ba479bcdede94d5a703de2871e2"
+dependencies = [
+ "futures-core",
+]
+
+[[package]]
+name = "futures-core"
+version = "0.3.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c09fd04b7e4073ac7156a9539b57a484a8ea920f79c7c675d05d289ab6110d3"
 
 [[package]]
 name = "futures-io"
-version = "0.3.15"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "acc499defb3b348f8d8f3f66415835a9131856ff7714bf10dadfc4ec4bdb29a1"
+checksum = "fc4045962a5a5e935ee2fdedaa4e08284547402885ab326734432bed5d12966b"
+
+[[package]]
+name = "futures-lite"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97999970129b808f0ccba93211201d431fcc12d7e1ffae03a61b5cedd1a7ced2"
+dependencies = [
+ "fastrand",
+ "futures-core",
+ "futures-io",
+ "memchr",
+ "parking 2.0.0",
+ "pin-project-lite 0.1.12",
+ "waker-fn",
+]
+
+[[package]]
+name = "futures-macro"
+version = "0.3.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33c1e13800337f4d4d7a316bf45a567dbcb6ffe087f16424852d97e97a91f512"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "futures-task"
+version = "0.3.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c66a976bf5909d801bbef33416c41372779507e7a6b3a5e25e4749c58f776a"
 
 [[package]]
 name = "futures-timer"
-version = "2.0.2"
+version = "3.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1de7508b218029b0f01662ed8f61b1c964b3ae99d6f25462d0f55a595109df6"
+checksum = "e64b03909df88034c26dc1547e8970b91f98bdb65165d6a4e9110d94263dbb2c"
+dependencies = [
+ "gloo-timers",
+ "send_wrapper",
+]
+
+[[package]]
+name = "futures-util"
+version = "0.3.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d8b7abd5d659d9b90c8cba917f6ec750a74e2dc23902ef9cd4cc8c8b22e6036a"
+dependencies = [
+ "futures-core",
+ "futures-io",
+ "futures-macro",
+ "futures-task",
+ "memchr",
+ "pin-project-lite 0.2.6",
+ "pin-utils",
+ "slab",
+]
 
 [[package]]
 name = "getrandom"
@@ -456,6 +527,18 @@ version = "0.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0e4075386626662786ddb0ec9081e7c7eeb1ba31951f447ca780ef9f5d568189"
 
+[[package]]
+name = "gloo-timers"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4d12a7f4e95cfe710f1d624fb1210b7d961a5fb05c4fd942f4feab06e61f590e"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.18"
@@ -547,21 +630,21 @@ dependencies = [
  "cfg-if 1.0.0",
 ]
 
-[[package]]
-name = "iovec"
-version = "0.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b2b3ea6ff95e175473f8ffe6a7eb7c00d054240321b84c57051175fe3c1e075e"
-dependencies = [
- "libc",
-]
-
 [[package]]
 name = "itoa"
 version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dd25036021b0de88a0aff6b850051563c6516d0bf53f8638938edbb9de732736"
 
+[[package]]
+name = "js-sys"
+version = "0.3.56"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a38fc24e30fd564ce974c02bf1d337caddff65be6cc4735a1f7eab22a7440f04"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "kernel32-sys"
 version = "0.2.2"
@@ -595,10 +678,10 @@ checksum = "5b9d21a790e85496a97d9b82821aa39c59579433e9ad29d7c1ab54d9807ebfcc"
 dependencies = [
  "amq-protocol",
  "async-task 4.0.3",
- "crossbeam-channel 0.5.1",
+ "crossbeam-channel",
  "futures-core",
  "log 0.4.14",
- "mio 0.7.11",
+ "mio",
  "parking_lot",
  "pinky-swear",
  "serde",
@@ -687,12 +770,6 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
 
-[[package]]
-name = "maybe-uninit"
-version = "2.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
-
 [[package]]
 name = "md5"
 version = "0.3.8"
@@ -705,15 +782,6 @@ version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b16bd47d9e329435e309c58469fe0791c2d0d1ba96ec0954152a5ae2b04387dc"
 
-[[package]]
-name = "memoffset"
-version = "0.5.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "043175f069eda7b85febe4a74abbaeff828d9f8b448515d3151a14a3542811aa"
-dependencies = [
- "autocfg",
-]
-
 [[package]]
 name = "mime"
 version = "0.2.6"
@@ -733,25 +801,6 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "mio"
-version = "0.6.23"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4afd66f5b91bf2a3bc13fad0e21caedac168ca4c707504e75585648ae80e4cc4"
-dependencies = [
- "cfg-if 0.1.10",
- "fuchsia-zircon",
- "fuchsia-zircon-sys",
- "iovec",
- "kernel32-sys",
- "libc",
- "log 0.4.14",
- "miow 0.2.2",
- "net2",
- "slab",
- "winapi 0.2.8",
-]
-
 [[package]]
 name = "mio"
 version = "0.7.11"
@@ -760,34 +809,11 @@ checksum = "cf80d3e903b34e0bd7282b218398aec54e082c840d9baf8339e0080a0c542956"
 dependencies = [
  "libc",
  "log 0.4.14",
- "miow 0.3.7",
+ "miow",
  "ntapi",
  "winapi 0.3.9",
 ]
 
-[[package]]
-name = "mio-uds"
-version = "0.6.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "afcb699eb26d4332647cc848492bbc15eafb26f08d0304550d5aa1f612e066f0"
-dependencies = [
- "iovec",
- "libc",
- "mio 0.6.23",
-]
-
-[[package]]
-name = "miow"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ebd808424166322d4a38da87083bfddd3ac4c131334ed55856112eb06d46944d"
-dependencies = [
- "kernel32-sys",
- "net2",
- "winapi 0.2.8",
- "ws2_32-sys",
-]
-
 [[package]]
 name = "miow"
 version = "0.3.7"
@@ -815,17 +841,6 @@ dependencies = [
  "tempfile 3.2.0",
 ]
 
-[[package]]
-name = "net2"
-version = "0.2.37"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "391630d12b68002ae1e25e8f974306474966550ad82dac6886fb8910c19568ae"
-dependencies = [
- "cfg-if 0.1.10",
- "libc",
- "winapi 0.3.9",
-]
-
 [[package]]
 name = "nom"
 version = "4.2.3"
@@ -904,6 +919,7 @@ dependencies = [
  "chrono",
  "either",
  "fs2",
+ "futures-util",
  "hubcaps",
  "hyper",
  "hyper-native-tls",
@@ -969,6 +985,18 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "parking"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6cb300f271742d4a2a66c01b6b2fa0c83dfebd2e0bf11addb879a3547b4ed87c"
+
+[[package]]
+name = "parking"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "427c3892f9e783d91cc128285287e70a59e206ca452770ece88a76f7a3eddd72"
+
 [[package]]
 name = "parking_lot"
 version = "0.11.1"
@@ -1245,6 +1273,12 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "scoped-tls"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea6a9290e3c9cf0f18145ef7ffa62d68ee0bf5fcd651017e586dc7fd5da448c2"
+
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -1274,6 +1308,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "send_wrapper"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f638d531eccd6e23b980caf34876660d38e265409d8e99b397ab71eb3612fad0"
+
 [[package]]
 name = "separator"
 version = "0.4.1"
@@ -1332,6 +1372,38 @@ version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
 
+[[package]]
+name = "smol"
+version = "0.1.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "620cbb3c6e34da57d3a248cda0cd01cd5848164dc062e764e65d06fe3ea7aed5"
+dependencies = [
+ "async-task 3.0.0",
+ "blocking",
+ "concurrent-queue",
+ "fastrand",
+ "futures-io",
+ "futures-util",
+ "libc",
+ "once_cell",
+ "scoped-tls",
+ "slab",
+ "socket2",
+ "wepoll-sys-stjepang",
+ "winapi 0.3.9",
+]
+
+[[package]]
+name = "socket2"
+version = "0.3.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "122e570113d28d773067fab24266b66753f6ea915758651696b6e35e49f88d6e"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "static_assertions"
 version = "1.1.0"
@@ -1372,7 +1444,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a29af643fc448ecb2d9b8a74aa2c60c72c36cb447bcf490b866797b58f00f13"
 dependencies = [
  "cfg-if 1.0.0",
- "mio 0.7.11",
+ "mio",
  "native-tls",
  "pem",
 ]
@@ -1618,12 +1690,103 @@ version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5fecdca9a5291cc2b8dcf7dc02453fee791a280f3743cb0905f8822ae463b3fe"
 
+[[package]]
+name = "waker-fn"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d5b2c62b4012a3e1eca5a7e077d13b3bf498c4073e33ccd58626607748ceeca"
+
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.79"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25f1af7423d8588a3d840681122e72e6a24ddbcb3f0ec385cac0d12d24256c06"
+dependencies = [
+ "cfg-if 1.0.0",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.79"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b21c0df030f5a177f3cba22e9bc4322695ec43e7257d865302900290bcdedca"
+dependencies = [
+ "bumpalo",
+ "lazy_static",
+ "log 0.4.14",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-futures"
+version = "0.4.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2eb6ec270a31b1d3c7e266b999739109abce8b6c87e4b31fcfcd788b65267395"
+dependencies = [
+ "cfg-if 1.0.0",
+ "js-sys",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.79"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f4203d69e40a52ee523b2529a773d5ffc1dc0071801c87b3d270b471b80ed01"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.79"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa8a30d46208db204854cadbb5d4baf5fcf8071ba5bf48190c3e59937962ebc"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.79"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d958d035c4438e28c70e4321a2911302f10135ce78a9c7834c0cab4123d06a2"
+
+[[package]]
+name = "web-sys"
+version = "0.3.56"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c060b319f29dd25724f09a2ba1418f142f539b2be99fbf4d2d5a8f7330afb8eb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "wepoll-sys-stjepang"
+version = "1.0.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fdfbb03f290ca0b27922e8d48a0997b4ceea12df33269b9f75e713311eb178d"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -1658,16 +1821,6 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
-[[package]]
-name = "ws2_32-sys"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d59cefebd0c892fa2dd6de581e937301d8552cb44489cdff035c6187cb63fa5e"
-dependencies = [
- "winapi 0.2.8",
- "winapi-build",
-]
-
 [[package]]
 name = "wyz"
 version = "0.2.0"

ofborg/Cargo.toml

@@ -6,10 +6,11 @@ build = "build.rs"
 edition = "2018"
 
 [dependencies]
-async-std = "=1.5.0"
+async-std = { version = "=1.6.0", features = ["unstable"] }
 chrono = "0.4.6"
 either = "1.4.0"
 fs2 = "0.4.2"
+futures-util = "0.3.21"
 hubcaps = { git = "https://github.com/grahamc/hubcaps.git" }
 #hubcaps = { path = "../../../grahamc/hubcaps/" } # for testing patches
 hyper = "0.10.*"

ofborg/src/bin/builder.rs

@@ -2,7 +2,8 @@ use std::env;
 use std::error::Error;
 use std::path::Path;
 
-use async_std::task;
+use async_std::task::{self, JoinHandle};
+use futures_util::future;
 use tracing::{info, warn};
 
 use ofborg::easyamqp::{self, ChannelExt, ConsumerExt};
@@ -17,9 +18,6 @@ fn main() -> Result<(), Box<dyn Error>> {
     let arg = env::args().nth(1).expect("usage: builder <config>");
     let cfg = config::load(arg.as_ref());
 
-    let cloner = checkout::cached_cloner(Path::new(&cfg.checkout.root));
-    let nix = cfg.nix();
-
     if !cfg.feedback.full_logs {
         warn!("Please define feedback.full_logs in your configuration to true!");
         warn!("feedback.full_logs when true will cause the full build log to be sent back");
@@ -31,8 +29,41 @@ fn main() -> Result<(), Box<dyn Error>> {
     };
 
     let conn = easylapin::from_config(&cfg.rabbitmq)?;
+    let handle = self::create_handle(&conn, &cfg, None)?;
+
+    if let Some(ref additional_build_systems) = cfg.nix.additional_build_systems {
+        let mut handles = vec![handle];
+
+        for system in additional_build_systems {
+            let handle_ext = self::create_handle(&conn, &cfg, Some(system.to_string()))?;
+            handles.push(handle_ext);
+        }
+
+        task::block_on(future::join_all(handles));
+    } else {
+        task::block_on(handle);
+    }
+
+    drop(conn); // Close connection.
+    info!("Closed the session... EOF");
+    Ok(())
+}
+
+fn create_handle(
+    conn: &lapin::Connection,
+    cfg: &config::Config,
+    system_override: Option<String>,
+) -> Result<JoinHandle<()>, Box<dyn Error>> {
     let mut chan = task::block_on(conn.create_channel())?;
 
+    let cloner = checkout::cached_cloner(Path::new(&cfg.checkout.root));
+    let nix = if let Some(system) = system_override {
+        cfg.nix().with_system(String::from(system))
+    } else {
+        cfg.nix()
+    };
+    let system = nix.system.clone();
+
     chan.declare_exchange(easyamqp::ExchangeConfig {
         exchange: "build-jobs".to_owned(),
         exchange_type: easyamqp::ExchangeType::Fanout,
@@ -44,7 +75,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     })?;
 
     let queue_name = if cfg.runner.build_all_jobs != Some(true) {
-        let queue_name = format!("build-inputs-{}", cfg.nix.system);
+        let queue_name = format!("build-inputs-{}", system);
         chan.declare_queue(easyamqp::QueueConfig {
             queue: queue_name.clone(),
             passive: false,
@@ -77,12 +108,7 @@ fn main() -> Result<(), Box<dyn Error>> {
     })?;
 
     let handle = easylapin::NotifyChannel(chan).consume(
-        tasks::build::BuildWorker::new(
+        tasks::build::BuildWorker::new(cloner, nix, system, cfg.runner.identity.clone()),
-            cloner,
-            nix,
-            cfg.nix.system.clone(),
-            cfg.runner.identity.clone(),
-        ),
         easyamqp::ConsumeConfig {
             queue: queue_name.clone(),
             consumer_tag: format!("{}-builder", cfg.whoami()),
@@ -94,9 +120,5 @@ fn main() -> Result<(), Box<dyn Error>> {
     )?;
 
     info!("Fetching jobs from {}", &queue_name);
-    task::block_on(handle);
+    Ok(task::spawn(handle))
-
-    drop(conn); // Close connection.
-    info!("Closed the session... EOF");
-    Ok(())
 }

ofborg/src/config.rs

@@ -41,6 +41,7 @@ pub struct RabbitMqConfig {
 #[derive(Serialize, Deserialize, Debug)]
 pub struct NixConfig {
     pub system: String,
+    pub additional_build_systems: Option<Vec<String>>,
     pub remote: String,
     pub build_timeout_seconds: u16,
     pub initial_heap_size: Option<String>,

ofborg/src/easylapin.rs

@@ -155,9 +155,9 @@ impl<'a> NotificationReceiver for ChannelNotificationReceiver<'a> {
 // but one could probably be implemented in terms of the other instead.
 pub struct NotifyChannel(pub Channel);
 
-impl<'a, W: SimpleNotifyWorker + 'a> ConsumerExt<'a, W> for NotifyChannel {
+impl<'a, W: SimpleNotifyWorker + 'a + Send> ConsumerExt<'a, W> for NotifyChannel {
     type Error = lapin::Error;
-    type Handle = Pin<Box<dyn Future<Output = ()> + 'a>>;
+    type Handle = Pin<Box<dyn Future<Output = ()> + 'a + Send>>;
 
     fn consume(self, worker: W, config: ConsumeConfig) -> Result<Self::Handle, Self::Error> {
         task::block_on(self.0.basic_qos(1, BasicQosOptions::default()))?;

ofborg/src/nix.rs

@@ -97,7 +97,7 @@ impl fmt::Display for Operation {
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct Nix {
-    system: String,
+    pub system: String,
     remote: String,
     build_timeout: u16,
     limit_supported_systems: bool,