diff --git a/share/mk/bsd.progs.mk b/share/mk/bsd.progs.mk
index dce05c7d7bd..c84e94b7c87 100644
--- a/share/mk/bsd.progs.mk
+++ b/share/mk/bsd.progs.mk
@@ -31,7 +31,7 @@ UPDATE_DEPENDFILE_PROG = ${PROGS:[1]}
 # They may have asked us to build just one
 .for t in ${PROGS}
 .if make($t)
-.if ${PROGS_CXX:M${t}}
+.if ${PROGS_CXX:U:M${t}}
 PROG_CXX ?= $t
 .endif
 PROG ?= $t