crystal-on-cygwin.patch

diff --git a/src/exception.cr b/src/exception.cr
index cd4450c..570e2fd 100644
--- a/src/exception.cr
+++ b/src/exception.cr
@@ -21,7 +21,11 @@ struct CallStack
       makecontext_start = makecontext_end = LibDL.dlsym(LibDL::RTLD_DEFAULT, "makecontext")
 
       while true
-        ret = LibDL.dladdr(makecontext_end, out info)
+        ifdef cygwin
+          break
+        else
+          ret = LibDL.dladdr(makecontext_end, out info)
+        end
         break if ret == 0 || info.sname.nil?
         break unless LibC.strcmp(info.sname, "makecontext") == 0
         makecontext_end += 1
@@ -69,15 +73,18 @@ struct CallStack
   end
 
   protected def self.decode_frame(ip, original_ip = ip)
-    if LibDL.dladdr(ip, out info) != 0
-      offset = original_ip - info.saddr
+    ifdef cygwin
+    else
+      if LibDL.dladdr(ip, out info) != 0
+        offset = original_ip - info.saddr
 
-      if offset == 0
-        return decode_frame(ip - 1, original_ip)
-      end
+        if offset == 0
+          return decode_frame(ip - 1, original_ip)
+        end
 
-      unless info.sname.nil?
-        {offset, String.new(info.sname)}
+        unless info.sname.nil?
+          {offset, String.new(info.sname)}
+        end
       end
     end
   end
diff --git a/src/file/stat.cr b/src/file/stat.cr
index bddf6b8..9ec959d 100644
--- a/src/file/stat.cr
+++ b/src/file/stat.cr
@@ -62,6 +62,23 @@ lib LibC
         __unused5 : UInt64
       end
     end
+  elsif cygwin
+    struct Stat
+      st_dev : UInt32
+      st_ino : UInt64
+      st_mode : LibC::ModeT
+      st_nlink : UInt16
+      st_uid : UInt32
+      st_gid : UInt32
+      st_rdev : UInt32
+      st_size : Int64
+      st_atimespec : LibC::TimeSpec
+      st_mtimespec : LibC::TimeSpec
+      st_ctimespec : LibC::TimeSpec
+      st_blksize : Int64
+      st_blocks : Int64
+      st_birthtim : LibC::TimeSpec
+    end
   end
 
   S_ISVTX  = 0o001000
diff --git a/src/io.cr b/src/io.cr
index ae0139e..bbde887 100644
--- a/src/io.cr
+++ b/src/io.cr
@@ -26,6 +26,15 @@ lib LibC
     O_TRUNC    = 0x0400
     O_NONBLOCK = 0x0004
     O_CLOEXEC  = 0x1000000
+  elsif cygwin
+    O_RDONLY   = 0x0000
+    O_WRONLY   = 0x0001
+    O_RDWR     = 0x0002
+    O_APPEND   = 0x0008
+    O_CREAT    = 0x0200
+    O_TRUNC    = 0x0400
+    O_NONBLOCK = 0x4000
+    O_CLOEXEC  = 0x40000
   end
 
   S_IRWXU    = 0o000700         # RWX mask for owner
diff --git a/src/libc.cr b/src/libc.cr
index bfbe0dd..313fa0e 100644
--- a/src/libc.cr
+++ b/src/libc.cr
@@ -29,6 +29,8 @@ lib LibC
     alias ModeT = UInt16
   elsif linux
     alias ModeT = UInt32
+  elsif cygwin
+    alias ModeT = UInt32
   end
 
   ifdef darwin
@@ -57,6 +59,9 @@ lib LibC
   ifdef linux
     MAP_ANON = 0x0020
   end
+  ifdef cygwin
+    MAP_ANON = 0x20
+  end
 
   MAP_FAILED = Pointer(Void).new(SizeT.new(-1))
 

Was this ever submitted or accepted? Do you have any input on how to get crystal to even build on cygwin? All I get trying to install is the "you need to have a crystal executable in your path" obviously: crystal-lang/crystal#1331