bugfix: ensured the 'pcre_version' symbol is also preserved on Darwin platforms.

Follow-up commit to 5a97cce

Author: thibaultcha

config

@@ -450,22 +450,41 @@ ngx_feature_test='struct sigaction act;
 
 . auto/feature
 
-if [ $PCRE != NO -a $PCRE != YES ]; then
-    # force pcre_version symbol to be undefined when PCRE is statically linked
+if [ $USE_PCRE = YES -o $PCRE != NONE ] && [ $PCRE != NO -a $PCRE != YES ]; then
+    # force pcre_version symbol to be required when PCRE is statically linked
+    case "$NGX_PLATFORM" in
+        Darwin:*)
+            ngx_feature="require defined symbols (-u)"
+            ngx_feature_name=
+            ngx_feature_path=
+            ngx_feature_libs="-Wl,-u,_strerror"
+            ngx_feature_run=no
+            ngx_feature_incs="#include <stdio.h>"
+            ngx_feature_test='printf("hello");'
 
-    ngx_feature="force undefined symbols (--undefined)"
-    ngx_feature_libs="-Wl,--undefined=printf"
-    ngx_feature_name=
-    ngx_feature_run=no
-    ngx_feature_incs="#include <stdio.h>"
-    ngx_feature_path=
-    ngx_feature_test='printf("hello");'
+            . auto/feature
 
-    . auto/feature
+            if [ $ngx_found = yes ]; then
+                CORE_LIBS="-Wl,-u,_pcre_version $CORE_LIBS"
+            fi
+        ;;
 
-    if [ $ngx_found = yes ]; then
-        CORE_LIBS="$CORE_LIBS -Wl,--undefined=pcre_version"
-    fi
+        *)
+            ngx_feature="require defined symbols (--require-defined)"
+            ngx_feature_name=
+            ngx_feature_path=
+            ngx_feature_libs="-Wl,--require-defined=strerror"
+            ngx_feature_run=no
+            ngx_feature_incs="#include <stdio.h>"
+            ngx_feature_test='printf("hello");'
+
+            . auto/feature
+
+            if [ $ngx_found = yes ]; then
+                CORE_LIBS="-Wl,--require-defined=pcre_version $CORE_LIBS"
+            fi
+        ;;
+    esac
 fi
 
 #CFLAGS=$"$CFLAGS -DLUA_DEFAULT_PATH='\"/usr/local/openresty/lualib/?.lua\"'"