bzip2: add CPPFLAGS

Add the OpenWrt CPPFLAGS to the CFLAGS. bzip2 does not support CPPFLAGS.
This fixes fortify sources support.

Link: https://github.com/openwrt/openwrt/pull/22056
Signed-off-by: Hauke Mehrtens <[email protected]>

package/utils/bzip2/Makefile

@@ -62,7 +62,7 @@ CONFIGURE_ARGS += --prefix=/usr
 
 MAKE_FLAGS += \
 	-f Makefile-libbz2_so \
-	CFLAGS="$(TARGET_CFLAGS)" \
+	CFLAGS="$(TARGET_CFLAGS) $(TARGET_CPPFLAGS)" \
 	LDFLAGS="$(TARGET_LDFLAGS)" \
 	all
 
@@ -92,7 +92,7 @@ HOST_CFLAGS += \
 	$(FPIC)
 
 HOST_MAKE_FLAGS+= \
-	CFLAGS="$(HOST_CFLAGS)" \
+	CFLAGS="$(HOST_CFLAGS) $(HOST_CPPFLAGS)" \
 	LDFLAGS="$(HOST_LDFLAGS)" \
 	all