diff --git a/share/mk/bsd.lib.mk b/share/mk/bsd.lib.mk
index d1b8beb29852..a731cc5c1b9c 100644
--- a/share/mk/bsd.lib.mk
+++ b/share/mk/bsd.lib.mk
@@ -460,7 +460,7 @@ _libinstall:
 .include <bsd.nls.mk>
 .if defined(_COV_FLAG)
 _GCDA_SRCS=	${SRCS:M*.c} ${SRCS:M*.cc} ${SRCS:M*.cpp} ${SRCS:M*.cxx} ${SRCS:M*.C}
-GCDAS=		${_GCDA_SRCS:R:S/$/.gcda/g}
+GCDAS:=		${_GCDA_SRCS:R:S/$/.gcda/g}
 .undef _GCDA_SRCS
 .for _gcda in ${GCDAS}
 ${_gcda}: ${_gcda:R}.pico
diff --git a/share/mk/bsd.prog.mk b/share/mk/bsd.prog.mk
index 01447d4df1a8..247341b69745 100644
--- a/share/mk/bsd.prog.mk
+++ b/share/mk/bsd.prog.mk
@@ -307,7 +307,7 @@ NLSNAME?=	${PROG}
 .include <bsd.confs.mk>
 .if defined(_COV_FLAG)
 _GCDA_SRCS=	${SRCS:M*.c} ${SRCS:M*.cc} ${SRCS:M*.cpp} ${SRCS:M*.cxx} ${SRCS:M*.C}
-GCDAS=		${_GCDA_SRCS:R:S/$/.gcda/g}
+GCDAS:=		${_GCDA_SRCS:R:S/$/.gcda/g}
 .undef _GCDA_SRCS
 .for _gcda in ${GCDAS}
 ${_gcda}: ${_gcda:R}.pico