diff --git a/Makefile b/Makefile
index c6d38e5..8dbaa9f 100644
--- a/Makefile
+++ b/Makefile
@@ -29,8 +29,8 @@ OD ?= od
 
 OPT ?= -O3
 
-CXXFLAGS ?= -g $(OPT) -Wall -Wextra -Woverloaded-virtual -pedantic -std=c++0x -fPIC -Iinclude -Ithird_party/md5 -Ithird_party/json
-CFLAGS ?= -g $(OPT) -Wall -Wextra -pedantic -std=c99 -fPIC -Iinclude
+CXXFLAGS += -Wall -Wextra -Woverloaded-virtual -pedantic -std=c++0x -fPIC -Iinclude -Ithird_party/md5 -Ithird_party/json
+CFLAGS += -Wall -Wextra -pedantic -std=c99 -fPIC -Iinclude
 MAKEDEPENDFLAGS ?= -Iinclude -Ithird_party/md5 -Ithird_party/json
 EMCXXFLAGS = $(CXXFLAGS) -g0 -Os --memory-init-file 0 -s DISABLE_EXCEPTION_CATCHING=0 -s OUTLINING_LIMIT=10000 -s RESERVED_FUNCTION_POINTERS=20 -s ASSERTIONS=1 -s ALLOW_MEMORY_GROWTH=1
 EMCFLAGS = $(CFLAGS) --memory-init-file 0 -s DISABLE_EXCEPTION_CATCHING=0 -s ASSERTIONS=1 -s ALLOW_MEMORY_GROWTH=1
@@ -123,10 +123,10 @@ jsonnet: cmd/jsonnet.cpp $(LIB_OBJ)
 
 # C binding.
 libjsonnet.so: $(LIB_OBJ)
-	$(CXX) $(LDFLAGS) $(LIB_OBJ) $(SHARED_LDFLAGS) -o $@
+	$(CXX) $(LDFLAGS) $(LIB_OBJ) $(SHARED_LDFLAGS) -Wl,-soname,libjsonnet.so -o $@
 
 libjsonnet++.so: $(LIB_CPP_OBJ)
-	$(CXX) $(LDFLAGS) $(LIB_CPP_OBJ) $(SHARED_LDFLAGS) -o $@
+	$(CXX) $(LDFLAGS) $(LIB_CPP_OBJ) $(SHARED_LDFLAGS) -Wl,-soname,libjsonnet++.so -o $@
 
 # JavaScript build of C binding
 JS_EXPORTED_FUNCTIONS = 'EXPORTED_FUNCTIONS=["_jsonnet_make", "_jsonnet_evaluate_snippet", "_jsonnet_fmt_snippet", "_jsonnet_ext_var", "_jsonnet_ext_code", "_jsonnet_tla_var", "_jsonnet_tla_code", "_jsonnet_realloc", "_jsonnet_destroy", "_jsonnet_import_callback"]'