Enable static CRT linking for Linux targets (#424)

Change target-feature from -crt-static to +crt-static for gnu and musl
targets to create fully static, portable binaries.

Author: cong-or

earthly/rust/stdcfgs/cargo_config.toml

@@ -14,15 +14,15 @@
 linker = "clang"
 rustflags = [
     "-C", "link-arg=-fuse-ld=/usr/bin/mold",
-    "-C", "target-feature=-crt-static"
+    "-C", "target-feature=+crt-static"
 ]
 
 # Should be the default to have fully static rust programs in CI
 [target.aarch64-unknown-linux-musl]
 linker = "clang"
 rustflags = [
     "-C", "link-arg=-fuse-ld=/usr/bin/mold",
-    "-C", "target-feature=-crt-static"
+    "-C", "target-feature=+crt-static"
 ]
 
 [build]

examples/rust/.cargo/config.toml

@@ -14,15 +14,15 @@
 linker = "clang"
 rustflags = [
     "-C", "link-arg=-fuse-ld=/usr/bin/mold",
-    "-C", "target-feature=-crt-static"
+    "-C", "target-feature=+crt-static"
 ]
 
 # Should be the default to have fully static rust programs in CI
 [target.aarch64-unknown-linux-musl]
 linker = "clang"
 rustflags = [
     "-C", "link-arg=-fuse-ld=/usr/bin/mold",
-    "-C", "target-feature=-crt-static"
+    "-C", "target-feature=+crt-static"
 ]
 
 [build]