diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 79d102304470..a2335e402145 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -89,6 +89,9 @@ ifeq ($(CC_NO_CLANG), 1)
 EXTRA_WARNINGS += -Wstrict-aliasing=3
 
 else ifneq ($(CROSS_COMPILE),)
+# Allow userspace to override CLANG_CROSS_FLAGS to specify their own
+# sysroots and flags or to avoid the GCC call in pure Clang builds.
+ifeq ($(CLANG_CROSS_FLAGS),)
 CLANG_CROSS_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))
 GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)gcc 2>/dev/null))
 ifneq ($(GCC_TOOLCHAIN_DIR),)
@@ -96,6 +99,7 @@ CLANG_CROSS_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
 CLANG_CROSS_FLAGS += --sysroot=$(shell $(CROSS_COMPILE)gcc -print-sysroot)
 CLANG_CROSS_FLAGS += --gcc-toolchain=$(realpath $(GCC_TOOLCHAIN_DIR)/..)
 endif # GCC_TOOLCHAIN_DIR
+endif # CLANG_CROSS_FLAGS
 CFLAGS += $(CLANG_CROSS_FLAGS)
 AFLAGS += $(CLANG_CROSS_FLAGS)
 endif # CROSS_COMPILE