Deprecate `group_static_libs` property

We now default to lld for platform builds, removing all need for this
property.  For more details, see "Effecient archive file handling" in
https://lld.llvm.org/NewLLD.html#key-concepts

Bug: 189475744
Test: Manual build succeeds
Change-Id: If1104d68b13de8c7afab35c1741a68f64394b448
diff --git a/cc/builder.go b/cc/builder.go
index 842ce85..b6b00cb 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -384,9 +384,6 @@
 
 	systemIncludeFlags string
 
-	// True if static libraries should be grouped (using `-Wl,--start-group` and `-Wl,--end-group`).
-	groupStaticLibs bool
-
 	proto            android.ProtoFlags
 	protoC           bool // If true, compile protos as `.c` files. Otherwise, output as `.cc`.
 	protoOptionsFile bool // If true, output a proto options file.
@@ -752,13 +749,7 @@
 		}
 	}
 
-	if flags.groupStaticLibs && !ctx.Darwin() && len(staticLibs) > 0 {
-		libFlagsList = append(libFlagsList, "-Wl,--start-group")
-	}
 	libFlagsList = append(libFlagsList, staticLibs.Strings()...)
-	if flags.groupStaticLibs && !ctx.Darwin() && len(staticLibs) > 0 {
-		libFlagsList = append(libFlagsList, "-Wl,--end-group")
-	}
 
 	if groupLate && !ctx.Darwin() && len(lateStaticLibs) > 0 {
 		libFlagsList = append(libFlagsList, "-Wl,--start-group")
diff --git a/cc/cc.go b/cc/cc.go
index 9c1f559..b0c0299 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -217,8 +217,6 @@
 
 	// True if .s files should be processed with the c preprocessor.
 	AssemblerWithCpp bool
-	// True if static libraries should be grouped (using `-Wl,--start-group` and `-Wl,--end-group`).
-	GroupStaticLibs bool
 
 	proto            android.ProtoFlags
 	protoC           bool // Whether to use C instead of C++
diff --git a/cc/linker.go b/cc/linker.go
index 8671dec..0d612b5 100644
--- a/cc/linker.go
+++ b/cc/linker.go
@@ -86,8 +86,7 @@
 	// compiling crt or libc.
 	Nocrt *bool `android:"arch_variant"`
 
-	// group static libraries.  This can resolve missing symbols issues with interdependencies
-	// between static libraries, but it is generally better to order them correctly instead.
+	// deprecated and ignored because lld makes it unnecessary. See b/189475744.
 	Group_static_libs *bool `android:"arch_variant"`
 
 	// list of modules that should be installed with this module.  This is similar to 'required'
@@ -543,10 +542,6 @@
 
 	flags.Global.LdFlags = append(flags.Global.LdFlags, toolchain.ToolchainLdflags())
 
-	if Bool(linker.Properties.Group_static_libs) {
-		flags.GroupStaticLibs = true
-	}
-
 	// Version_script is not needed when linking stubs lib where the version
 	// script is created from the symbol map file.
 	if !linker.dynamicProperties.BuildStubs {
diff --git a/cc/util.go b/cc/util.go
index 9bba876..88b0aba 100644
--- a/cc/util.go
+++ b/cc/util.go
@@ -91,7 +91,6 @@
 		systemIncludeFlags: strings.Join(in.SystemIncludeFlags, " "),
 
 		assemblerWithCpp: in.AssemblerWithCpp,
-		groupStaticLibs:  in.GroupStaticLibs,
 
 		proto:            in.proto,
 		protoC:           in.protoC,