Configure: pcre.lib dependencies fix.

Previously, an attempt to build pcre.lib on win32 before anything else
failed due to no pcre.h.
diff --git a/auto/lib/pcre/make b/auto/lib/pcre/make
index 834779b..c50d12f 100644
--- a/auto/lib/pcre/make
+++ b/auto/lib/pcre/make
@@ -32,7 +32,8 @@
 
         cat << END                                            >> $NGX_MAKEFILE
 
-`echo "$PCRE/pcre.lib:	$NGX_MAKEFILE" | sed -e "s/\//$ngx_regex_dirsep/g"`
+`echo "$PCRE/pcre.lib:	$PCRE/pcre.h $NGX_MAKEFILE"			\
+	| sed -e "s/\//$ngx_regex_dirsep/g"`
 	\$(MAKE) -f auto/lib/pcre/$ngx_makefile $ngx_pcre $ngx_opt
 
 `echo "$PCRE/pcre.h:" | sed -e "s/\//$ngx_regex_dirsep/g"`