https://listman.redhat.com/archives/dm-devel/2023-March/053587.html

From 2ebbff587e80f3f153b934d3cfcccb8a4bb21568 Mon Sep 17 00:00:00 2001
From: Sam James <sam@gentoo.org>
Date: Thu, 23 Mar 2023 08:04:49 +0000
Subject: [PATCH] tests: fix quoting of CFLAGS in Makefile

Otherwise, when CFLAGS/CPPFLAGS have multiple entries (like "-O2 -pipe"), we
get an error:
```
make[1]: Entering directory '/var/tmp/portage/sys-fs/multipath-tools-0.9.4/work/multipath-tools-0.9.4/tests'
/bin/sh: line 1: -pipe: command not found
make[1]: *** [Makefile:115: libmultipath.so.0] Error 127
make[1]: *** Waiting for unfinished jobs....
```

Signed-off-by: Sam James <sam@gentoo.org>
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -112,7 +112,7 @@ dep_clean:
 # Pass the original values of CFLAGS etc. to the sub-make, which will include
 # Makefile.in again. Otherwise, the flags would be added twice.
 libmultipath.so.0: $(multipathdir)/libmultipath.so.0
-	@CFLAGS=$(ORIG_CFLAGS) CPPFLAGS=$(ORIG_CPPFLAGS) LDFLAGS=$(ORIG_LDFLAGS) \
+	@CFLAGS="$(ORIG_CFLAGS)" CPPFLAGS="$(ORIG_CPPFLAGS)" LDFLAGS="$(ORIG_LDFLAGS)" \
 	$(MAKE) -C $(multipathdir) configdir=$(TESTDIR)/conf.d plugindir=$(TESTDIR)/lib test-lib
 
 # COLON will get expanded during second expansion below
-- 
2.40.0