Add support for Rust C libraries.

Adds the ability for rust modules to be compiled as C libraries, and
allows cc modules to depend on these rust-generated modules. This also
means that soong-rust should not have any dependencies on soong-cc aside
from what's required for testing.

There's a couple small fixes included as well:

 - A bug in libNameFromFilePath that caused issues when library's had
 "lib" in their name.
 - VariantName is removed from rust library MutatedProperties since this
 was unused.

Bug: 140726209
Test: Soong tests pass.
Test: Example cc_binary can include a rust shared library as a dep.
Test: m crosvm.experimental
Change-Id: Ia7deed1345d2423001089014cc65ce7934123da4
diff --git a/rust/library_test.go b/rust/library_test.go
index bf8643e..66bcd20 100644
--- a/rust/library_test.go
+++ b/rust/library_test.go
@@ -29,19 +29,37 @@
 			crate_name: "foo",
 		}`)
 
-	// Test both variants are being built.
+	// Test all variants are being built.
 	libfooRlib := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_rlib").Output("libfoo.rlib")
-	libfooDylib := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_dylib").Output("libfoo.so")
+	libfooDylib := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_dylib").Output("libfoo.dylib.so")
+	libfooStatic := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_static").Output("libfoo.a")
+	libfooShared := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_shared").Output("libfoo.so")
+
+	rlibCrateType := "rlib"
+	dylibCrateType := "dylib"
+	sharedCrateType := "cdylib"
+	staticCrateType := "static"
 
 	// Test crate type for rlib is correct.
-	if !strings.Contains(libfooRlib.Args["rustcFlags"], "crate-type=rlib") {
-		t.Errorf("missing crate-type for libfoo rlib, rustcFlags: %#v", libfooRlib.Args["rustcFlags"])
+	if !strings.Contains(libfooRlib.Args["rustcFlags"], "crate-type="+rlibCrateType) {
+		t.Errorf("missing crate-type for static variant, expecting %#v, rustcFlags: %#v", rlibCrateType, libfooRlib.Args["rustcFlags"])
 	}
 
 	// Test crate type for dylib is correct.
-	if !strings.Contains(libfooDylib.Args["rustcFlags"], "crate-type=dylib") {
-		t.Errorf("missing crate-type for libfoo dylib, rustcFlags: %#v", libfooDylib.Args["rustcFlags"])
+	if !strings.Contains(libfooDylib.Args["rustcFlags"], "crate-type="+dylibCrateType) {
+		t.Errorf("missing crate-type for static variant, expecting %#v, rustcFlags: %#v", dylibCrateType, libfooDylib.Args["rustcFlags"])
 	}
+
+	// Test crate type for C static libraries is correct.
+	if !strings.Contains(libfooStatic.Args["rustcFlags"], "crate-type="+staticCrateType) {
+		t.Errorf("missing crate-type for static variant, expecting %#v, rustcFlags: %#v", staticCrateType, libfooStatic.Args["rustcFlags"])
+	}
+
+	// Test crate type for C shared libraries is correct.
+	if !strings.Contains(libfooShared.Args["rustcFlags"], "crate-type="+sharedCrateType) {
+		t.Errorf("missing crate-type for shared variant, expecting %#v, got rustcFlags: %#v", sharedCrateType, libfooShared.Args["rustcFlags"])
+	}
+
 }
 
 // Test that dylibs are not statically linking the standard library.
@@ -53,7 +71,7 @@
 			crate_name: "foo",
 		}`)
 
-	libfooDylib := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_dylib").Output("libfoo.so")
+	libfooDylib := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_dylib").Output("libfoo.dylib.so")
 
 	if !strings.Contains(libfooDylib.Args["rustcFlags"], "prefer-dynamic") {
 		t.Errorf("missing prefer-dynamic flag for libfoo dylib, rustcFlags: %#v", libfooDylib.Args["rustcFlags"])