diff --git a/Rules.mak b/Rules.mak
index 58a4c3e70..6df828c7c 100644
--- a/Rules.mak
+++ b/Rules.mak
@@ -174,6 +174,7 @@ CHECKED_CFLAGS+=$(call check_cc,$(CC),-Wshadow,)
 CHECKED_CFLAGS+=$(call check_cc,$(CC),-funsigned-char,)
 CHECKED_CFLAGS+=$(call check_cc,$(CC),-mmax-stack-frame=256,)
 CHECKED_CFLAGS+=$(call check_cc,$(CC),-fno-builtin-strlen)
+CHECKED_CFLAGS+=$(call check_cc,$(CC),-finline-limit=0)
 
 # Preemptively pin this too.
 PROG_CFLAGS:=
diff --git a/include/libbb.h b/include/libbb.h
index db43984b8..6d6213901 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -551,4 +551,19 @@ extern uint32_t *bb_crc32_filltable (int endian);
 
 extern const char BB_BANNER[];
 
+// Make sure we call functions instead of macros.
+#undef isalnum
+#undef isalpha
+#undef isascii
+#undef isblank
+#undef iscntrl
+#undef isdigit
+#undef isgraph
+#undef islower
+#undef isprint
+#undef ispunct
+#undef isspace
+#undef isupper
+#undef isxdigit
+
 #endif /* __LIBBUSYBOX_H__ */