diff --git a/ci/config.mk.clang.sed b/ci/config.mk.clang.sed
index 40c6705..da6044d 100644
--- a/ci/config.mk.clang.sed
+++ b/ci/config.mk.clang.sed
@@ -1 +1,2 @@
-/^RUBY_CFLAGS\b/s/$/ -Wno-error=unknown-attributes -Wno-error=ignored-attributes/
+/^CFLAGS[[:blank:]]*=/s/$/ -Wno-error=missing-field-initializers/
+/^RUBY_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unknown-attributes -Wno-error=ignored-attributes/
diff --git a/ci/config.mk.gcc.sed b/ci/config.mk.gcc.sed
index 3b11569..f46e488 100644
--- a/ci/config.mk.gcc.sed
+++ b/ci/config.mk.gcc.sed
@@ -1 +1 @@
-/^CFLAGS\b/s/$/ -Wno-error=maybe-uninitialized/
+/^CFLAGS[[:blank:]]*=/s/$/ -Wno-error=maybe-uninitialized/
diff --git a/ci/config.mk.sed b/ci/config.mk.sed
index 3168278..cd2cd9c 100644
--- a/ci/config.mk.sed
+++ b/ci/config.mk.sed
@@ -1,2 +1,2 @@
-/^CFLAGS\b/s/$/ -Wall -Wextra -Wshadow -Werror/
-/^PERL_CFLAGS\b/s/$/ -Wno-error=unused-function/
+/^CFLAGS[[:blank:]]*=/s/$/ -Wall -Wextra -Wshadow -Werror/
+/^PERL_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unused-function/