readme: add information about OpenSSL library dependencies
@@ -42,13 +42,21 @@ Note that the information in this section is preliminary. Please open an issue f
### Prerequisites
-This project requires LLVM, Python 2, and git to build.
+This project requires **LLVM**, **Python 2**, and **OpenSSL libraries** to build.
To see which version of LLVM/Clang is available, use `clang --version`.
We recommend version 8, but also had successes to build Skia with 6.0.1 and 7.0.1, and - on macOS - Apple LLVM version 10. So it's probably best to use the preinstalled version or install version 8 if LLVM is not available on your platform by default.
-Python version 2.7 _should_ be available. The build script probes for `python --version` and `python2 --version` and uses the first one that looks like a version 2 executable.
+Python version 2.7 _must_ be available. The build script probes for `python --version` and `python2 --version` and uses the first one that looks like a version 2 executable.
+
+OpenSSL libraries can be installed on **Debian** and **Ubuntu** with:
+
+```bash
+sudo apt-get install pkg-config libssl-dev
+```
+
+For other platforms, more information is available at the [OpenSSL crate documentation](https://docs.rs/openssl/0.10.24/openssl/#automatic).
### macOS
