ci.yml: Set RUSTDOCFLAGS to statically link doctests

Prior to Rust 1.89, these tests were just skipped when cross-compiling.
Now, they are actually compiled and ran. Unfortunately, doctests don't
use the normal RUSTFLAGS environment variable, so we also need to set
RUSTDOCFLAGS or else the resulting dynamically linked executable will
fail to run on a non-Android host.

Upstream change: rust-lang/cargo#15462

Signed-off-by: Andrew Gunnerson <accounts+github@chiller3.com>

Author: chenxiaolong

.github/workflows/ci.yml

@@ -11,6 +11,8 @@ jobs:
       CARGO_TERM_COLOR: always
       # https://github.com/rust-lang/rust/issues/78210
       RUSTFLAGS: -C strip=symbols -C target-feature=+crt-static
+      # https://github.com/rust-lang/cargo/pull/15462
+      RUSTDOCFLAGS: -C target-feature=+crt-static
       TARGETS: ${{ join(matrix.artifact.targets, ' ') || matrix.artifact.name }}
       ANDROID_API: ${{ matrix.artifact.android_api }}
     strategy: