diff -up ustr-1.0.4/Makefile.orig2 ustr-1.0.4/Makefile
--- ustr-1.0.4/Makefile.orig2	2023-04-17 17:41:55.289194228 +0800
+++ ustr-1.0.4/Makefile	2023-04-17 17:41:58.941200484 +0800
@@ -28,7 +28,7 @@ MBINDIR=$(libexecdir)/ustr-$(VERS_FULL)
 ###############################################################################
 HIDE=@
 
-CC = cc
+CC ?= cc
 AR = ar
 RANLIB = ranlib
 LDCONFIG = /sbin/ldconfig