Changes for C to C++. Adding extern C to header files for compatibility.
diff --git a/Makefile b/Makefile
index 517ddfd..7f657ef 100644
--- a/Makefile
+++ b/Makefile
@@ -3205,7 +3205,7 @@
src/core/ext/filters/message_size/message_size_filter.c \
src/core/ext/filters/workarounds/workaround_cronet_compression_filter.c \
src/core/ext/filters/workarounds/workaround_utils.c \
- src/core/plugin_registry/grpc_plugin_registry.c \
+ src/core/plugin_registry/grpc_plugin_registry.cc \
PUBLIC_HEADERS_C += \
include/grpc/impl/codegen/byte_buffer.h \
@@ -3514,7 +3514,7 @@
src/core/ext/transport/chttp2/client/chttp2_connector.c \
src/core/ext/filters/load_reporting/server_load_reporting_filter.c \
src/core/ext/filters/load_reporting/server_load_reporting_plugin.c \
- src/core/plugin_registry/grpc_cronet_plugin_registry.c \
+ src/core/plugin_registry/grpc_cronet_plugin_registry.cc \
PUBLIC_HEADERS_C += \
include/grpc/impl/codegen/byte_buffer.h \
@@ -4323,7 +4323,7 @@
src/core/ext/filters/message_size/message_size_filter.c \
src/core/ext/filters/workarounds/workaround_cronet_compression_filter.c \
src/core/ext/filters/workarounds/workaround_utils.c \
- src/core/plugin_registry/grpc_unsecure_plugin_registry.c \
+ src/core/plugin_registry/grpc_unsecure_plugin_registry.cc \
PUBLIC_HEADERS_C += \
include/grpc/impl/codegen/byte_buffer.h \
@@ -20188,8 +20188,8 @@
src/core/lib/security/transport/tsi_error.c: $(OPENSSL_DEP)
src/core/lib/security/util/json_util.c: $(OPENSSL_DEP)
src/core/lib/surface/init_secure.c: $(OPENSSL_DEP)
-src/core/plugin_registry/grpc_cronet_plugin_registry.c: $(OPENSSL_DEP)
-src/core/plugin_registry/grpc_plugin_registry.c: $(OPENSSL_DEP)
+src/core/plugin_registry/grpc_cronet_plugin_registry.cc: $(OPENSSL_DEP)
+src/core/plugin_registry/grpc_plugin_registry.cc: $(OPENSSL_DEP)
src/core/tsi/fake_transport_security.c: $(OPENSSL_DEP)
src/core/tsi/gts_transport_security.c: $(OPENSSL_DEP)
src/core/tsi/ssl_transport_security.c: $(OPENSSL_DEP)
