Auto merge of #1176 - xmclark:add-signal-and-raise-windows, r=alexcrichton

add signal and raise bindings for windows

This PR adds `signal` and `raise` bindings for windows.

I don't know these functions or linux very well, so I leaned on other overrides of signal in the linux bindings, and the [cppreference page](https://en.cppreference.com/w/cpp/header/csignal) for adding the bindings.

I added some constants that were shown on the [microsoft signal page](https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/signal?view=vs-2017) and used the default values I found spelunking through my own copy of `signal.h` that came along with visual studio.

The automated tests pass and my toy apps use the `signal` and `raise` as expected. Let me know if there is anything else I need to do, or any extra tests to write.

EDIT:
currently working on getting a nice isolated msys2 environment I can use to dev against.
- [x] msys2 env setup and building

Author: bors

libc-test/build.rs

@@ -76,6 +76,7 @@ fn main() {
         cfg.header("windows.h");
         cfg.header("process.h");
         cfg.header("ws2ipdef.h");
+        cfg.header("signal.h");
 
         if target.contains("gnu") {
             cfg.header("ws2tcpip.h");
@@ -372,7 +373,9 @@ fn main() {
             // Fixup a few types on windows that don't actually exist.
             "time64_t" if windows => "__time64_t".to_string(),
             "ssize_t" if windows => "SSIZE_T".to_string(),
-
+            // windows 
+            "sighandler_t" if windows && !mingw => "_crt_signal_t".to_string(),
+            "sighandler_t" if windows && mingw => "__p_sig_fn_t".to_string(),
             // OSX calls this something else
             "sighandler_t" if bsdlike => "sig_t".to_string(),
 
@@ -507,6 +510,7 @@ fn main() {
             n if n.starts_with("P") => true,
             n if n.starts_with("H") => true,
             n if n.starts_with("LP") => true,
+            "__p_sig_fn_t" if mingw => true,
             _ => false,
         }
     });

src/windows/gnu.rs

@@ -4,5 +4,5 @@ pub const TMP_MAX: ::c_uint = 0x7fff;
 extern {
     pub fn strcasecmp(s1: *const ::c_char, s2: *const ::c_char) -> ::c_int;
     pub fn strncasecmp(s1: *const ::c_char, s2: *const ::c_char,
-                    n: ::size_t) -> ::c_int;
+                       n: ::size_t) -> ::c_int;
 }

src/windows/mod.rs

@@ -27,6 +27,7 @@ pub type ptrdiff_t = isize;
 pub type intptr_t = isize;
 pub type uintptr_t = usize;
 pub type ssize_t = isize;
+pub type sighandler_t = usize;
 
 pub type c_char = i8;
 pub type c_long = i32;
@@ -177,6 +178,16 @@ pub const ENOTEMPTY: ::c_int = 41;
 pub const EILSEQ: ::c_int = 42;
 pub const STRUNCATE: ::c_int = 80;
 
+// signal codes
+pub const SIGINT: ::c_int = 2;
+pub const SIGILL: ::c_int = 4;
+pub const SIGFPE: ::c_int = 8;
+pub const SIGSEGV: ::c_int = 11;
+pub const SIGTERM: ::c_int = 15;
+pub const SIGABRT: ::c_int = 22;
+pub const NSIG: ::c_int = 23;
+pub const SIG_ERR: ::c_int = -1;
+
 // inline comment below appeases style checker
 #[cfg(all(target_env = "msvc", feature = "rustc-dep-of-std"))] // " if "
 #[link(name = "msvcrt", cfg(not(target_feature = "crt-static")))]
@@ -287,6 +298,9 @@ extern {
     pub fn rand() -> c_int;
     pub fn srand(seed: c_uint);
 
+    pub fn signal(signum: c_int, handler: sighandler_t) -> sighandler_t;
+    pub fn raise(signum: c_int) -> c_int;
+
     #[link_name = "_chmod"]
     pub fn chmod(path: *const c_char, mode: ::c_int) -> ::c_int;
     #[link_name = "_wchmod"]

src/windows/msvc.rs

@@ -7,4 +7,4 @@ extern {
     #[link_name = "_strnicmp"]
     pub fn strnicmp(s1: *const ::c_char, s2: *const ::c_char,
                     n: ::size_t) -> ::c_int;
-}
+}