build: don't use vendored OpenSSL by default

I added support for using a vendored OpenSSL in dbadbd68c0. That was
in order to get the musl binary to work. However, it shouldn't be
needed on most platforms, and we've had a few reports of issues caused
by it. Let's disable it by default and enable it specifically when
building the musl binary instead.

.github/workflows/release.yml

@@ -41,6 +41,9 @@ jobs:
         target: ${{ matrix.target }}
     - name: Build release binary
       run: cargo build --target ${{ matrix.target }} --verbose --release
+    - name: (re-)Build release binary with vendored OpenSSL
+      if: matrix.os != 'ubuntu-20.04' && matrix.os != 'macos-11'
+      run: cargo build --target ${{ matrix.target }} --verbose --release --features vendored-openssl
     - name: Build archive
       shell: bash
       run: |

Cargo.toml

@@ -75,5 +75,5 @@ test-case = "2.2.2"
 testutils = { path = "lib/testutils" }
 
 [features]
-default = ["vendored-openssl", "jujutsu-lib/legacy-thrift"]
+default = ["jujutsu-lib/legacy-thrift"]
 vendored-openssl = ["git2/vendored-openssl", "jujutsu-lib/vendored-openssl"]

README.md

@@ -231,7 +231,7 @@ cargo install --git https://github.com/martinvonz/jj.git --bin jj jujutsu
 
 Run:
 ```shell script
-cargo install --git https://github.com/martinvonz/jj.git --bin jj jujutsu
+cargo install --git https://github.com/martinvonz/jj.git --bin jj jujutsu --features vendored-openssl
 ```