Move default crt objects into Toolchain

Move the crt objects spread around cc/library.go and cc/binary.go
into the Toolchain.  This will simplify adding new toolchains that
have custom crt objects.

Test: m checkbuild
Test: go test ./cc/...
Change-Id: I7fdc1f53769799cb9c10e3e5816dabee0f918768
diff --git a/cc/config/bionic.go b/cc/config/bionic.go
index 0258408..e87f571 100644
--- a/cc/config/bionic.go
+++ b/cc/config/bionic.go
@@ -19,8 +19,19 @@
 
 var (
 	bionicDefaultSharedLibraries = []string{"libc", "libm", "libdl"}
+
+	bionicCrtBeginStaticBinary, bionicCrtEndStaticBinary   = []string{"crtbegin_static"}, []string{"crtend_android"}
+	bionicCrtBeginSharedBinary, bionicCrtEndSharedBinary   = []string{"crtbegin_dynamic"}, []string{"crtend_android"}
+	bionicCrtBeginSharedLibrary, bionicCrtEndSharedLibrary = []string{"crtbegin_so"}, []string{"crtend_so"}
 )
 
 func (toolchainBionic) Bionic() bool { return true }
 
 func (toolchainBionic) DefaultSharedLibraries() []string { return bionicDefaultSharedLibraries }
+
+func (toolchainBionic) CrtBeginStaticBinary() []string  { return bionicCrtBeginStaticBinary }
+func (toolchainBionic) CrtBeginSharedBinary() []string  { return bionicCrtBeginSharedBinary }
+func (toolchainBionic) CrtBeginSharedLibrary() []string { return bionicCrtBeginSharedLibrary }
+func (toolchainBionic) CrtEndStaticBinary() []string    { return bionicCrtEndStaticBinary }
+func (toolchainBionic) CrtEndSharedBinary() []string    { return bionicCrtEndSharedBinary }
+func (toolchainBionic) CrtEndSharedLibrary() []string   { return bionicCrtEndSharedLibrary }