Fixed the ngx_regex.h header file compatibility with C++.

src/core/ngx_regex.c

diff --git a/src/core/ngx_regex.c b/src/core/ngx_regex.c
index 677f862..3771aab 100644
--- a/src/core/ngx_regex.c
+++ b/src/core/ngx_regex.c
@@ -152,7 +152,7 @@
         return NGX_ERROR;
     }
 
-    rc->regex->pcre = re;
+    rc->regex->code = re;
 
     /* do not study at runtime */
 
@@ -367,7 +367,7 @@
             i = 0;
         }
 
-        elts[i].regex->extra = pcre_study(elts[i].regex->pcre, opt, &errstr);
+        elts[i].regex->extra = pcre_study(elts[i].regex->code, opt, &errstr);
 
         if (errstr != NULL) {
             ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
@@ -380,7 +380,7 @@
             int jit, n;
 
             jit = 0;
-            n = pcre_fullinfo(elts[i].regex->pcre, elts[i].regex->extra,
+            n = pcre_fullinfo(elts[i].regex->code, elts[i].regex->extra,
                               PCRE_INFO_JIT, &jit);
 
             if (n != 0 || jit != 1) {

src/core/ngx_regex.h

diff --git a/src/core/ngx_regex.h b/src/core/ngx_regex.h
index 55bd331..680486c 100644
--- a/src/core/ngx_regex.h
+++ b/src/core/ngx_regex.h
@@ -21,7 +21,7 @@
 
 
 typedef struct {
-    pcre        *pcre;
+    pcre        *code;
     pcre_extra  *extra;
 } ngx_regex_t;
 
@@ -50,7 +50,7 @@
 ngx_int_t ngx_regex_compile(ngx_regex_compile_t *rc);
 
 #define ngx_regex_exec(re, s, captures, size)                                \
-    pcre_exec(re->pcre, re->extra, (const char *) (s)->data, (s)->len, 0, 0, \
+    pcre_exec(re->code, re->extra, (const char *) (s)->data, (s)->len, 0, 0, \
               captures, size)
 #define ngx_regex_exec_n      "pcre_exec()"