Support facebook's cinder.3.8 Python fork (#631)

* Capture build metadata in version struct

Also include the build metada in the version struct.

* Support facebook's cinder.3.8 Python fork

Facebook's cinder.3.8 Python fork uses a different offset for the
current tstate.  Use the buildmetadata to detect and special case this
(https://github.com/facebookincubator/cinder/blob/cinder/3.8/Include/patchlevel.h#L26).

src/coredump.rs

@@ -441,6 +441,7 @@ mod test {
             minor: 9,
             patch: 13,
             release_flags: "".to_owned(),
+            build_metadata: None,
         };
         let python_core = PythonCoreDump {
             core,

src/python_bindings/mod.rs

@@ -222,7 +222,10 @@ pub mod pyruntime {
             },
             Version {
                 major: 3, minor: 8, ..
-            } => Some(1368),
+            } => match version.build_metadata.as_deref() {
+                Some("cinder") => Some(1384),
+                _ => Some(1368),
+            },
             Version {
                 major: 3,
                 minor: 9..=10,

src/python_process_info.rs

@@ -318,6 +318,7 @@ where
                             minor,
                             patch: 0,
                             release_flags: "".to_owned(),
+                            build_metadata: None,
                         });
                     }
                 }

src/version.rs

@@ -9,6 +9,7 @@ pub struct Version {
     pub minor: u64,
     pub patch: u64,
     pub release_flags: String,
+    pub build_metadata: Option<String>,
 }
 
 impl Version {
@@ -28,6 +29,11 @@ impl Version {
             let major = std::str::from_utf8(&cap[2])?.parse::<u64>()?;
             let minor = std::str::from_utf8(&cap[3])?.parse::<u64>()?;
             let patch = std::str::from_utf8(&cap[4])?.parse::<u64>()?;
+            let build_metadata = if let Some(s) = cap.get(7) {
+                Some(std::str::from_utf8(&s.as_bytes()[1..])?.to_owned())
+            } else {
+                None
+            };
 
             let version = std::str::from_utf8(&cap[0])?;
             info!("Found matching version string '{}'", version);
@@ -47,6 +53,7 @@ impl Version {
                 minor,
                 patch,
                 release_flags: release.to_owned(),
+                build_metadata,
             });
         }
         Err(format_err!("failed to find version string"))
@@ -59,7 +66,11 @@ impl std::fmt::Display for Version {
             f,
             "{}.{}.{}{}",
             self.major, self.minor, self.patch, self.release_flags
-        )
+        )?;
+        if let Some(build_metadata) = &self.build_metadata {
+            write!(f, "+{}", build_metadata,)?
+        }
+        Ok(())
     }
 }
 
@@ -75,7 +86,8 @@ mod tests {
                 major: 2,
                 minor: 7,
                 patch: 10,
-                release_flags: "".to_owned()
+                release_flags: "".to_owned(),
+                build_metadata: None,
             }
         );
 
@@ -89,7 +101,8 @@ mod tests {
                 major: 3,
                 minor: 6,
                 patch: 3,
-                release_flags: "".to_owned()
+                release_flags: "".to_owned(),
+                build_metadata: None,
             }
         );
 
@@ -102,7 +115,8 @@ mod tests {
                 major: 3,
                 minor: 7,
                 patch: 0,
-                release_flags: "rc1".to_owned()
+                release_flags: "rc1".to_owned(),
+                build_metadata: None,
             }
         );
 
@@ -115,7 +129,8 @@ mod tests {
                 major: 3,
                 minor: 10,
                 patch: 0,
-                release_flags: "rc1".to_owned()
+                release_flags: "rc1".to_owned(),
+                build_metadata: None,
             }
         );
 
@@ -137,7 +152,8 @@ mod tests {
                 major: 2,
                 minor: 7,
                 patch: 15,
-                release_flags: "".to_owned()
+                release_flags: "".to_owned(),
+                build_metadata: Some("".to_owned()),
             }
         );
 
@@ -148,7 +164,8 @@ mod tests {
                 major: 2,
                 minor: 7,
                 patch: 10,
-                release_flags: "".to_owned()
+                release_flags: "".to_owned(),
+                build_metadata: Some("dcba".to_owned()),
             }
         );
 
@@ -159,7 +176,20 @@ mod tests {
                 major: 2,
                 minor: 7,
                 patch: 10,
-                release_flags: "".to_owned()
+                release_flags: "".to_owned(),
+                build_metadata: Some("5-4.abcd".to_owned()),
+            }
+        );
+
+        let version = Version::scan_bytes(b"2.8.5+cinder (default)").unwrap();
+        assert_eq!(
+            version,
+            Version {
+                major: 2,
+                minor: 8,
+                patch: 5,
+                release_flags: "".to_owned(),
+                build_metadata: Some("cinder".to_owned()),
             }
         );
     }