depends: empty spaces in PATH variable cause build failure

contrib/depends/funcs.mk

@@ -135,9 +135,9 @@ $(1)_config_env+=$($(1)_config_env_$(host_arch)_$(host_os)) $($(1)_config_env_$(
 
 $(1)_config_env+=PKG_CONFIG_LIBDIR=$($($(1)_type)_prefix)/lib/pkgconfig
 $(1)_config_env+=PKG_CONFIG_PATH=$($($(1)_type)_prefix)/share/pkgconfig
-$(1)_config_env+=PATH=$(build_prefix)/bin:$(PATH)
-$(1)_build_env+=PATH=$(build_prefix)/bin:$(PATH)
-$(1)_stage_env+=PATH=$(build_prefix)/bin:$(PATH)
+$(1)_config_env+=PATH="$(build_prefix)/bin:$(PATH)"
+$(1)_build_env+=PATH="$(build_prefix)/bin:$(PATH)"
+$(1)_stage_env+=PATH="$(build_prefix)/bin:$(PATH)"
 $(1)_autoconf=./configure --host=$($($(1)_type)_host) --disable-dependency-tracking --prefix=$($($(1)_type)_prefix) $$($(1)_config_opts) CC="$$($(1)_cc)" CXX="$$($(1)_cxx)"
 
 ifneq ($($(1)_nm),)