Configure: shared sources for addon modules.

Addon modules, both dynamic and static, can now use shared source files.
Shared sources result in only one make rule even if specified several
times in different modules.

auto/make

@@ -502,6 +502,7 @@ fi
 for ngx_module in $DYNAMIC_MODULES
 do
     eval ngx_module_srcs="\$${ngx_module}_SRCS"
+    eval ngx_module_shrd="\$${ngx_module}_SHRD"
     eval eval ngx_module_libs="\\\"\$${ngx_module}_LIBS\\\""
 
     eval ngx_module_modules="\$${ngx_module}_MODULES"
@@ -567,7 +568,7 @@ END
         | sed -e "s/\(.*\.\)c/\1$ngx_objext/"`
 
     ngx_module_objs=
-    for ngx_src in $ngx_module_srcs
+    for ngx_src in $ngx_module_srcs $ngx_module_shrd
     do
         case "$ngx_src" in
             src/*)

auto/module

@@ -17,7 +17,6 @@ if [ "$ngx_module_link" = DYNAMIC ]; then
     done
 
     DYNAMIC_MODULES="$DYNAMIC_MODULES $ngx_module"
-    eval ${ngx_module}_SRCS=\"$ngx_module_srcs\"
 
     eval ${ngx_module}_MODULES=\"$ngx_module_name\"
 
@@ -31,6 +30,30 @@ if [ "$ngx_module_link" = DYNAMIC ]; then
         eval ${ngx_module}_ORDER=\"$ngx_module_order\"
     fi
 
+    srcs=
+    shrd=
+    for src in $ngx_module_srcs
+    do
+        found=no
+        for old in $DYNAMIC_MODULES_SRCS
+        do
+            if [ $src = $old ]; then
+                found=yes
+                break
+            fi
+        done
+
+        if [ $found = no ]; then
+            srcs="$srcs $src"
+        else
+            shrd="$shrd $src"
+        fi
+    done
+    eval ${ngx_module}_SRCS=\"$srcs\"
+    eval ${ngx_module}_SHRD=\"$shrd\"
+
+    DYNAMIC_MODULES_SRCS="$DYNAMIC_MODULES_SRCS $srcs"
+
     if test -n "$ngx_module_incs"; then
         CORE_INCS="$CORE_INCS $ngx_module_incs"
     fi
@@ -107,7 +130,24 @@ elif [ "$ngx_module_link" = ADDON ]; then
     eval ${ngx_module_type}_MODULES=\"\$${ngx_module_type}_MODULES \
                                       $ngx_module_name\"
 
-    NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_module_srcs"
+    srcs=
+    for src in $ngx_module_srcs
+    do
+        found=no
+        for old in $NGX_ADDON_SRCS
+        do
+            if [ $src = $old ]; then
+                found=yes
+                break
+            fi
+        done
+
+        if [ $found = no ]; then
+            srcs="$srcs $src"
+        fi
+    done
+
+    NGX_ADDON_SRCS="$NGX_ADDON_SRCS $srcs"
 
     if test -n "$ngx_module_incs"; then
         eval ${ngx_var}_INCS=\"\$${ngx_var}_INCS $ngx_module_incs\"

auto/options

@@ -132,6 +132,7 @@ STREAM_UPSTREAM_ZONE=YES
 STREAM_SSL_PREREAD=NO
 
 DYNAMIC_MODULES=
+DYNAMIC_MODULES_SRCS=
 
 NGX_ADDONS=
 NGX_ADDON_SRCS=