diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc
--- a/lib/libc/gen/Makefile.inc
+++ b/lib/libc/gen/Makefile.inc
@@ -168,7 +168,7 @@
 	valloc.c \
 	wordexp.c
 
-.if ${COMPILER_TYPE} == "clang"
+.if ${COMPILER_FEATURES:Mblocks}
 CFLAGS.fts.c= -fblocks
 .endif
 
diff --git a/lib/libc/tests/gen/Makefile b/lib/libc/tests/gen/Makefile
--- a/lib/libc/tests/gen/Makefile
+++ b/lib/libc/tests/gen/Makefile
@@ -7,7 +7,7 @@
 ATF_TESTS_C+=		fmtmsg_test
 ATF_TESTS_C+=		fnmatch2_test
 ATF_TESTS_C+=		fpclassify2_test
-.if ${COMPILER_TYPE} == "clang"
+.if ${COMPILER_FEATURES:Mblocks}
 ATF_TESTS_C+=		fts_blocks_test
 .endif
 ATF_TESTS_C+=		ftw_test
diff --git a/lib/libc/tests/stdlib/Makefile b/lib/libc/tests/stdlib/Makefile
--- a/lib/libc/tests/stdlib/Makefile
+++ b/lib/libc/tests/stdlib/Makefile
@@ -7,7 +7,7 @@
 ATF_TESTS_C+=		libc_exit_test
 ATF_TESTS_C+=		mergesort_test
 ATF_TESTS_C+=		qsort_test
-.if ${COMPILER_TYPE} == "clang"
+.if ${COMPILER_FEATURES:Mblocks}
 ATF_TESTS_C+=		qsort_b_test
 .endif
 ATF_TESTS_C+=		qsort_r_compat_test
diff --git a/share/mk/bsd.compiler.mk b/share/mk/bsd.compiler.mk
--- a/share/mk/bsd.compiler.mk
+++ b/share/mk/bsd.compiler.mk
@@ -245,6 +245,7 @@
 ${X_}COMPILER_FEATURES+=	init-all
 .endif
 .if ${${X_}COMPILER_TYPE} == "clang"
+${X_}COMPILER_FEATURES+=	blocks
 ${X_}COMPILER_FEATURES+=	retpoline
 # PR257638 lld fails with BE compressed debug.  Fixed in main but external tool
 # chains will initially not have the fix.  For now limit the feature to LE