diff --git a/src/test/run-make/tools.mk b/src/test/run-make/tools.mk
index 483a5db877846..d4862e1570434 100644
--- a/src/test/run-make/tools.mk
+++ b/src/test/run-make/tools.mk
@@ -1,12 +1,9 @@
-export LD_LIBRARY_PATH:=$(TMPDIR):$(LD_LIBRARY_PATH)
-export DYLD_LIBRARY_PATH:=$(TMPDIR):$(DYLD_LIBRARY_PATH)
-
 # These deliberately use `=` and not `:=` so that client makefiles can
 # augment HOST_RPATH_DIR / TARGET_RPATH_DIR.
 HOST_RPATH_ENV = \
-    $(LD_LIB_PATH_ENVVAR)=$(HOST_RPATH_DIR):$$$(LD_LIB_PATH_ENVVAR)
+    $(LD_LIB_PATH_ENVVAR)="$(HOST_RPATH_DIR):$($(LD_LIB_PATH_ENVVAR))"
 TARGET_RPATH_ENV = \
-    $(LD_LIB_PATH_ENVVAR)=$(TARGET_RPATH_DIR):$$$(LD_LIB_PATH_ENVVAR)
+    $(LD_LIB_PATH_ENVVAR)="$(TARGET_RPATH_DIR):$($(LD_LIB_PATH_ENVVAR))"
 
 RUSTC := $(HOST_RPATH_ENV) $(RUSTC) --out-dir $(TMPDIR) -L $(TMPDIR)
 CC := $(CC) -L $(TMPDIR)
@@ -43,7 +40,6 @@ DYLIB_GLOB = $(1)*.dll
 DYLIB = $(TMPDIR)/$(1).dll
 BIN = $(1).exe
 RPATH_LINK_SEARCH =
-RUSTC := PATH="$(PATH):$(LD_LIBRARY_PATH)" $(RUSTC)
 else
 RUN = $(TARGET_RPATH_ENV) $(RUN_BINFILE)
 FAIL = $(TARGET_RPATH_ENV) $(RUN_BINFILE) && exit 1 || exit 0