This patch has been backported from the master branch.

--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,15 +28,15 @@
 filetime = "0.1"
 flate2 = "1.0"
 fs2 = "0.4"
-git2 = "0.6"
-git2-curl = "0.7"
+git2 = "0.7"
+git2-curl = "0.8"
 glob = "0.2"
 hex = "0.2"
 home = "0.3"
 ignore = "^0.2.2"
 jobserver = "0.1.6"
 libc = "0.2"
-libgit2-sys = "0.6"
+libgit2-sys = "0.7"
 log = "0.3"
 num_cpus = "1.0"
 same-file = "0.1"
--- a/src/cargo/ops/cargo_package.rs
+++ b/src/cargo/ops/cargo_package.rs
@@ -146,7 +146,7 @@ fn check_not_dirty(p: &Package, src: &PathSource) -> CargoResult<()> {
             let path = p.manifest_path();
             let path = path.strip_prefix(workdir).unwrap_or(path);
             if let Ok(status) = repo.status_file(path) {
-                if (status & git2::STATUS_IGNORED).is_empty() {
+                if (status & git2::Status::IGNORED).is_empty() {
                     debug!("Cargo.toml found in repo, checking if dirty");
                     return git(p, src, &repo)
                 }
@@ -165,7 +165,7 @@ fn check_not_dirty(p: &Package, src: &PathSource) -> CargoResult<()> {
         let dirty = src.list_files(p)?.iter().filter(|file| {
             let relative = file.strip_prefix(workdir).unwrap();
             if let Ok(status) = repo.status_file(relative) {
-                status != git2::STATUS_CURRENT
+                status != git2::Status::CURRENT
             } else {
                 false
             }
--- a/src/cargo/sources/git/utils.rs
+++ b/src/cargo/sources/git/utils.rs
@@ -431,7 +431,7 @@ fn with_authentication<T, F>(url: &str, cfg: &git2::Config, mut f: F)
         // usernames during one authentication session with libgit2, so to
         // handle this we bail out of this authentication session after setting
         // the flag `ssh_username_requested`, and then we handle this below.
-        if allowed.contains(git2::USERNAME) {
+        if allowed.contains(git2::CredentialType::USERNAME) {
             debug_assert!(username.is_none());
             ssh_username_requested = true;
             return Err(git2::Error::from_str("gonna try usernames later"))
@@ -445,7 +445,7 @@ fn with_authentication<T, F>(url: &str, cfg: &git2::Config, mut f: F)
         // If we get called with this then the only way that should be possible
         // is if a username is specified in the URL itself (e.g. `username` is
         // Some), hence the unwrap() here. We try custom usernames down below.
-        if allowed.contains(git2::SSH_KEY) && !tried_sshkey {
+        if allowed.contains(git2::CredentialType::SSH_KEY) && !tried_sshkey {
             // If ssh-agent authentication fails, libgit2 will keep
             // calling this callback asking for other authentication
             // methods to try. Make sure we only try ssh-agent once,
@@ -462,7 +462,7 @@ fn with_authentication<T, F>(url: &str, cfg: &git2::Config, mut f: F)
         // but we currently don't! Right now the only way we support fetching a
         // plaintext password is through the `credential.helper` support, so
         // fetch that here.
-        if allowed.contains(git2::USER_PASS_PLAINTEXT) {
+        if allowed.contains(git2::CredentialType::USER_PASS_PLAINTEXT) {
             let r = git2::Cred::credential_helper(cfg, url, username);
             cred_helper_bad = Some(r.is_err());
             return r
@@ -470,7 +470,7 @@ fn with_authentication<T, F>(url: &str, cfg: &git2::Config, mut f: F)
 
         // I'm... not sure what the DEFAULT kind of authentication is, but seems
         // easy to support?
-        if allowed.contains(git2::DEFAULT) {
+        if allowed.contains(git2::CredentialType::DEFAULT) {
             return git2::Cred::default()
         }
 
@@ -507,10 +507,10 @@ fn with_authentication<T, F>(url: &str, cfg: &git2::Config, mut f: F)
             // we bail out.
             let mut attempts = 0;
             res = f(&mut |_url, username, allowed| {
-                if allowed.contains(git2::USERNAME) {
+                if allowed.contains(git2::CredentialType::USERNAME) {
                     return git2::Cred::username(&s);
                 }
-                if allowed.contains(git2::SSH_KEY) {
+                if allowed.contains(git2::CredentialType::SSH_KEY) {
                     debug_assert_eq!(Some(&s[..]), username);
                     attempts += 1;
                     if attempts == 1 {
--- a/src/cargo/sources/path.rs
+++ b/src/cargo/sources/path.rs
@@ -327,7 +327,7 @@ impl<'cfg> PathSource<'cfg> {
         let statuses = repo.statuses(Some(&mut opts))?;
         let untracked = statuses.iter().filter_map(|entry| {
             match entry.status() {
-                git2::STATUS_WT_NEW => Some((join(root, entry.path_bytes()), None)),
+                git2::Status::WT_NEW => Some((join(root, entry.path_bytes()), None)),
                 _ => None,
             }
         });
--- a/tests/cargotest/Cargo.toml
+++ b/tests/cargotest/Cargo.toml
@@ -10,7 +10,7 @@ path = "lib.rs"
 cargo = { path = "../../.." }
 filetime = "0.1"
 flate2 = "1.0"
-git2 = { version = "0.6", default-features = false }
+git2 = { version = "0.7", default-features = false }
 hamcrest = "=0.1.1"
 hex = "0.3"
 log = "0.4"
--- a/tests/cargotest/support/git.rs
+++ b/tests/cargotest/support/git.rs
@@ -97,7 +97,7 @@ pub fn add(repo: &git2::Repository) {
         t!(submodule.add_to_index(false));
     }
     let mut index = t!(repo.index());
-    t!(index.add_all(["*"].iter(), git2::ADD_DEFAULT,
+    t!(index.add_all(["*"].iter(), git2::IndexAddOption::DEFAULT,
                   Some(&mut (|a, _b| {
         if s.iter().any(|s| a.starts_with(s.path())) {1} else {0}
     }))));