In our builds Config_heavy.pl sometimes has lines:
cwarnflags=XXX
ccstdflags=XXX
and sometimes does not.
The reason is that this information is pulled from cflags by configpm and yet
there is no dependency in the Makefile. Add one to fix this.

Upstream-Status: Submitted [https://github.com/arsv/perl-cross/pull/89]
RP 2020/2/19
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

Index: perl-5.30.1/Makefile
===================================================================
--- perl-5.30.1.orig/Makefile
+++ perl-5.30.1/Makefile
@@ -204,7 +204,7 @@ configpod: $(CONFIGPOD)
 git_version.h lib/Config_git.pl: make_patchnum.pl | miniperl$X
 	./miniperl_top make_patchnum.pl
 
-lib/Config.pm lib/Config_heavy.pl lib/Config.pod: config.sh \
+lib/Config.pm lib/Config_heavy.pl lib/Config.pod: config.sh cflags \
 		lib/Config_git.pl Porting/Glossary | miniperl$X
 	./miniperl_top configpm