!44 support clang build

From: @guojunding 
Reviewed-by: @dillon_chen 
Signed-off-by: @dillon_chen

acpica-tools.spec

@@ -1,6 +1,6 @@
 Name:           acpica-tools
 Version:        20210604
-Release:        4
+Release:        5
 Summary:        Tools for OS-independent reference implementation of ACPI
 
 License:        GPLv2
@@ -55,6 +55,10 @@ CWARNINGFLAGS="\
 export OPT_CFLAGS="%{optflags} $CWARNINGFLAGS"
 export OPT_LDFLAGS="%{__global_ldflags}"
 
+%if "%{?toolchain}" == "clang"
+    CFLAGS="${CFLAGS:-%{?build_cflags}}"; export CFLAGS;
+%endif
+
 %make_build
 
 %install
@@ -86,6 +90,9 @@ fi
 %{_docdir}/*
 
 %changelog
+* Wed Mar 6 2024 guojunding <guojunding@kylinos.cn> - 20210604-5
+- support clang build
+
 * Tue Mar 5 2024 guojunding <guojunding@kylinos.cn> - 20210604-4
 - fix invalid dates