Remove TARGET_LIBGCC/LIBATOMIC/LIBGCOV

Instead, use the libgcc/libatomic/libgcov from the static libraries dir,
which is provided by Soong. Copy the libraries using the Soong script if
Soong is disabled - this can be removed once USE_SOONG is removed.

Change-Id: Iad2ad20ad5c3cfc48bf1e46e594a482609098d7a
diff --git a/core/main.mk b/core/main.mk
index 3309981..83c60e5 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -291,6 +291,12 @@
 # Bring in standard build system definitions.
 include $(BUILD_SYSTEM)/definitions.mk
 
+ifneq ($(USE_SOONG),true)
+$(eval $(call copy-toolchain-library,libgcc))
+$(eval $(call copy-toolchain-library,libatomic))
+$(eval $(call copy-toolchain-library,libgcov))
+endif
+
 # Bring in dex_preopt.mk
 include $(BUILD_SYSTEM)/dex_preopt.mk