fix: use $(MAKE) instead of make for recursive make (close #1128).

Makefile

@@ -46,8 +46,8 @@ JSREGEXP005_PATH=deps/jsregexp005
 jsregexp:
 	git submodule init
 	git submodule update
-	make "INCLUDE_DIR=-I'$(shell pwd)/deps/lua51_include/'" LDLIBS="${LUA_LDLIBS}" -C "${JSREGEXP_PATH}"
-	make "INCLUDE_DIR=-I'$(shell pwd)/deps/lua51_include/'" LDLIBS="${LUA_LDLIBS}" -C "${JSREGEXP005_PATH}"
+	$(MAKE) "INCLUDE_DIR=-I'$(shell pwd)/deps/lua51_include/'" LDLIBS="${LUA_LDLIBS}" -C "${JSREGEXP_PATH}"
+	$(MAKE) "INCLUDE_DIR=-I'$(shell pwd)/deps/lua51_include/'" LDLIBS="${LUA_LDLIBS}" -C "${JSREGEXP005_PATH}"
 
 install_jsregexp: jsregexp
 	# remove old binary.
@@ -79,6 +79,6 @@ test: nvim install_jsregexp
 	export TEST_FILE=$(realpath ${TEST_FILE}); \
 	export BUSTED_ARGS=--lpath=$(shell pwd)/tests/?.lua; \
 	set -e; \
-	if ${TEST_07}; then make -C ${NVIM_0.7_PATH} functionaltest DEPS_CMAKE_FLAGS=-DUSE_BUNDLED_GPERF=OFF; fi; \
-	if ${TEST_09}; then make -C ${NVIM_0.9_PATH} functionaltest; fi; \
-	if ${TEST_MASTER}; then make -C ${NVIM_MASTER_PATH} functionaltest; fi;
+	if ${TEST_07}; then $(MAKE) -C ${NVIM_0.7_PATH} functionaltest DEPS_CMAKE_FLAGS=-DUSE_BUNDLED_GPERF=OFF; fi; \
+	if ${TEST_09}; then $(MAKE) -C ${NVIM_0.9_PATH} functionaltest; fi; \
+	if ${TEST_MASTER}; then $(MAKE) -C ${NVIM_MASTER_PATH} functionaltest; fi;