Implement VRE options with hard linkage to PCRE options instead

of maintaining magic hex-bit values that must match.

include/vre.h

@@ -48,8 +48,8 @@ typedef struct vre vre_t;
 #define VRE_ERROR_NOMATCH         (-1)
 
 /* And those to PCRE options */
-#define VRE_CASELESS           0x00000001
-#define VRE_NOTEMPTY_ATSTART   0x10000000
+extern const unsigned VRE_CASELESS;
+extern const unsigned VRE_NOTEMPTY_ATSTART;
 
 vre_t *VRE_compile(const char *, int, const char **, int *);
 int VRE_exec(const vre_t *code, const char *subject, int length,

lib/libvarnish/vre.c

@@ -39,6 +39,19 @@ struct vre {
 	pcre *re;
 };
 
+/*
+ * We don't want to spread or even expose the majority of PCRE options
+ * so we establish our own options and implement hard linkage to PCRE
+ * here.
+ */
+const unsigned VRE_CASELESS = PCRE_CASELESS;
+const unsigned VRE_NOTEMPTY_ATSTART =
+#ifdef PCRE_NOTEMPTY_ATSTART
+	PCRE_NOTEMPTY_ATSTART;
+#else
+	0;
+#endif
+
 vre_t *
 VRE_compile(const char *pattern, int options,
 		    const char **errptr, int *erroffset)