Add compatibilty with rust-stable.

  * Add feature flag for const-fn functionality, which simplifies some
    things and lets this crate run on architectures where atomic CAS
    isn't available (e.g., thumbv6).

  * Remove `const fn` where necessary to compile under rust-stable.

  * BREAKING CHANGE - Change signature of `Handler::replace` to take a
    mutable borrow. This is required because the underlying type is
    now a NonNull, which needs `mut`. The old behavior was never
    desired, but a consequence of trying to avoid `Option` by using a
    default handler.

  * Use lazy_static crate for initialization of Handler/HandlerArray.

  * Specify Sync for Handler. This is not amazing, since it isn't, but
    it's necessary for initialization in static contexts inside
    `lazy_static`. This should be fine, because any actual
    manipulation of the handler is done in unsafe functions.

1 files changed, 45 insertions, 0 deletions

diff --git a/Cargo.lock b/Cargo.lock
index cfcfe67..0b5518f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -77,6 +77,7 @@ dependencies = [
  "compiletest_rs 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "cortex-m 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cortex-m-rt 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -95,6 +96,7 @@ dependencies = [
  "serde 1.0.90 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.90 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tester 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -185,6 +187,15 @@ version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "kernel32-sys"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "lazy_static"
 version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -389,6 +400,25 @@ dependencies = [
 ]
 
 [[package]]
+name = "term"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "tester"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "getopts 0.2.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "term 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "thread_local"
 version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -436,6 +466,11 @@ dependencies = [
 
 [[package]]
 name = "winapi"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "winapi"
 version = "0.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
@@ -444,6 +479,11 @@ dependencies = [
 ]
 
 [[package]]
+name = "winapi-build"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "winapi-i686-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -474,6 +514,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum generic-array 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3c0f28c2f5bfb5960175af447a2da7c18900693738343dc896ffbcabd9839592"
 "checksum getopts 0.2.19 (registry+https://github.com/rust-lang/crates.io-index)" = "72327b15c228bfe31f1390f93dd5e9279587f0463836393c9df719ce62a3e450"
 "checksum itoa 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "501266b7edd0174f8530248f87f99c88fbe60ca4ef3dd486835b8d8d53136f7f"
+"checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bc5729f27f159ddd61f4df6228e827e86643d4d3e7c32183cb30a1c08f604a14"
 "checksum libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)" = "c6785aa7dd976f5fbf3b71cfd9cd49d7f783c1ff565a858d71031c6c313aa5c6"
 "checksum log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c84ec4b527950aa83a329754b01dbe3f58361d1c5efacd1f6d68c494d08a17c6"
@@ -501,6 +542,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dba1a27d3efae4351c8051072d619e3ade2820635c3958d826bfea39d59b54c8"
 "checksum syn 0.15.33 (registry+https://github.com/rust-lang/crates.io-index)" = "ec52cd796e5f01d0067225a5392e70084acc4c0013fa71d55166d38a8b307836"
 "checksum synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "73687139bf99285483c96ac0add482c3776528beac1d97d444f6e91f203a2015"
+"checksum term 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "fa63644f74ce96fbeb9b794f66aff2a52d601cbd5e80f4b97123e3899f4570f1"
+"checksum tester 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5e812cb26c597f86a49b26dbb58b878bd2a2b4b93fc069dc39499228fe556ff6"
 "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
 "checksum typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "612d636f949607bdf9b123b4a6f6d966dedf3ff669f7f045890d3a4a73948169"
 "checksum ucd-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "535c204ee4d8434478593480b8f86ab45ec9aae0e83c568ca81abf0fd0e88f86"
@@ -509,6 +552,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum utf8-ranges 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "796f7e48bef87609f7ade7e06495a87d5cd06c7866e6a5cbfceffc558a243737"
 "checksum vcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "45c297f0afb6928cd08ab1ff9d95e99392595ea25ae1b5ecf822ff8764e57a0d"
 "checksum volatile-register 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0d67cb4616d99b940db1d6bd28844ff97108b498a6ca850e5b6191a532063286"
+"checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "f10e386af2b13e47c89e7236a7a14a086791a2b88ebad6df9bf42040195cf770"
+"checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"