Dynamic modules: dlopen() support.
diff --git a/auto/lib/openssl/conf b/auto/lib/openssl/conf
index 28a99b2..2187e5c 100644
--- a/auto/lib/openssl/conf
+++ b/auto/lib/openssl/conf
@@ -32,7 +32,6 @@
             CORE_DEPS="$CORE_DEPS $OPENSSL/.openssl/include/openssl/ssl.h"
             CORE_LIBS="$CORE_LIBS $OPENSSL/.openssl/lib/libssl.a"
             CORE_LIBS="$CORE_LIBS $OPENSSL/.openssl/lib/libcrypto.a"
-            CORE_LIBS="$CORE_LIBS $NGX_LIBDL"
 
             if [ "$NGX_PLATFORM" = win32 ]; then
                 CORE_LIBS="$CORE_LIBS -lgdi32 -lcrypt32 -lws2_32"
@@ -106,7 +105,7 @@
         if [ $ngx_found = yes ]; then
             have=NGX_SSL . auto/have
             CORE_INCS="$CORE_INCS $ngx_feature_path"
-            CORE_LIBS="$CORE_LIBS $ngx_feature_libs $NGX_LIBDL"
+            CORE_LIBS="$CORE_LIBS $ngx_feature_libs"
             OPENSSL=YES
         fi
     fi
diff --git a/auto/sources b/auto/sources
index d325ec3..9ea9e09 100644
--- a/auto/sources
+++ b/auto/sources
@@ -152,6 +152,7 @@
             src/os/unix/ngx_socket.h \
             src/os/unix/ngx_os.h \
             src/os/unix/ngx_user.h \
+            src/os/unix/ngx_dlopen.h \
             src/os/unix/ngx_process_cycle.h"
 
 # add to UNIX_DEPS
@@ -183,6 +184,7 @@
             src/os/unix/ngx_setproctitle.c \
             src/os/unix/ngx_posix_init.c \
             src/os/unix/ngx_user.c \
+            src/os/unix/ngx_dlopen.c \
             src/os/unix/ngx_process_cycle.c"
 
 POSIX_DEPS=src/os/unix/ngx_posix_config.h
@@ -228,6 +230,7 @@
             src/os/win32/ngx_socket.h \
             src/os/win32/ngx_os.h \
             src/os/win32/ngx_user.h \
+            src/os/win32/ngx_dlopen.h \
             src/os/win32/ngx_process_cycle.h"
 
 WIN32_CONFIG=src/os/win32/ngx_win32_config.h
@@ -248,6 +251,7 @@
             src/os/win32/ngx_wsasend_chain.c \
             src/os/win32/ngx_win32_init.c \
             src/os/win32/ngx_user.c \
+            src/os/win32/ngx_dlopen.c \
             src/os/win32/ngx_event_log.c \
             src/os/win32/ngx_process_cycle.c \
             src/event/ngx_event_acceptex.c"
diff --git a/auto/unix b/auto/unix
index 7bfca8f..6ca63a6 100755
--- a/auto/unix
+++ b/auto/unix
@@ -255,7 +255,7 @@
 
 
 ngx_feature="dlopen()"
-ngx_feature_name=
+ngx_feature_name="NGX_HAVE_DLOPEN"
 ngx_feature_run=no
 ngx_feature_incs="#include <dlfcn.h>"
 ngx_feature_path=
@@ -271,7 +271,7 @@
     . auto/feature
 
     if [ $ngx_found = yes ]; then
-        NGX_LIBDL="-ldl"
+        CORE_LIBS="$CORE_LIBS -ldl"
     fi
 fi
 
diff --git a/src/core/ngx_core.h b/src/core/ngx_core.h
index 2855a59..2819c1a 100644
--- a/src/core/ngx_core.h
+++ b/src/core/ngx_core.h
@@ -53,6 +53,7 @@
 #include <ngx_shmem.h>
 #include <ngx_process.h>
 #include <ngx_user.h>
+#include <ngx_dlopen.h>
 #include <ngx_parse.h>
 #include <ngx_parse_time.h>
 #include <ngx_log.h>
diff --git a/src/os/unix/ngx_darwin_config.h b/src/os/unix/ngx_darwin_config.h
index bbad977..cfe3ce2 100644
--- a/src/os/unix/ngx_darwin_config.h
+++ b/src/os/unix/ngx_darwin_config.h
@@ -48,6 +48,8 @@
 #include <sys/sysctl.h>
 #include <xlocale.h>
 
+#include <dlfcn.h>
+
 
 #ifndef IOV_MAX
 #define IOV_MAX   64
diff --git a/src/os/unix/ngx_dlopen.c b/src/os/unix/ngx_dlopen.c
new file mode 100644
index 0000000..a0efc69
--- /dev/null
+++ b/src/os/unix/ngx_dlopen.c
@@ -0,0 +1,28 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+#if (NGX_HAVE_DLOPEN)
+
+char *
+ngx_dlerror(void)
+{
+    char  *err;
+
+    err = (char *) dlerror();
+
+    if (err == NULL) {
+        return "";
+    }
+
+    return err;
+}
+
+#endif
diff --git a/src/os/unix/ngx_dlopen.h b/src/os/unix/ngx_dlopen.h
new file mode 100644
index 0000000..7a3159f
--- /dev/null
+++ b/src/os/unix/ngx_dlopen.h
@@ -0,0 +1,31 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#ifndef _NGX_DLOPEN_H_INCLUDED_
+#define _NGX_DLOPEN_H_INCLUDED_
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+#define ngx_dlopen(path)           dlopen((char *) path, RTLD_NOW | RTLD_GLOBAL)
+#define ngx_dlopen_n               "dlopen()"
+
+#define ngx_dlsym(handle, symbol)  dlsym(handle, symbol)
+#define ngx_dlsym_n                "dlsym()"
+
+#define ngx_dlclose(handle)        dlclose(handle)
+#define ngx_dlclose_n              "dlclose()"
+
+
+#if (NGX_HAVE_DLOPEN)
+char *ngx_dlerror(void);
+#endif
+
+
+#endif /* _NGX_DLOPEN_H_INCLUDED_ */
diff --git a/src/os/unix/ngx_freebsd_config.h b/src/os/unix/ngx_freebsd_config.h
index 9a25788..b7da48c 100644
--- a/src/os/unix/ngx_freebsd_config.h
+++ b/src/os/unix/ngx_freebsd_config.h
@@ -49,6 +49,8 @@
 #include <osreldate.h>
 #include <sys/sysctl.h>
 
+#include <dlfcn.h>
+
 
 #if __FreeBSD_version < 400017
 
diff --git a/src/os/unix/ngx_linux_config.h b/src/os/unix/ngx_linux_config.h
index 162a992..2f6129d 100644
--- a/src/os/unix/ngx_linux_config.h
+++ b/src/os/unix/ngx_linux_config.h
@@ -55,6 +55,8 @@
 #include <crypt.h>
 #include <sys/utsname.h>        /* uname() */
 
+#include <dlfcn.h>
+
 
 #include <ngx_auto_config.h>
 
diff --git a/src/os/unix/ngx_posix_config.h b/src/os/unix/ngx_posix_config.h
index 443c4b0..bf75997 100644
--- a/src/os/unix/ngx_posix_config.h
+++ b/src/os/unix/ngx_posix_config.h
@@ -108,6 +108,11 @@
 #include <ngx_auto_config.h>
 
 
+#if (NGX_HAVE_DLOPEN)
+#include <dlfcn.h>
+#endif
+
+
 #if (NGX_HAVE_POSIX_SEM)
 #include <semaphore.h>
 #endif
diff --git a/src/os/unix/ngx_solaris_config.h b/src/os/unix/ngx_solaris_config.h
index ddfd984..ffa01c8 100644
--- a/src/os/unix/ngx_solaris_config.h
+++ b/src/os/unix/ngx_solaris_config.h
@@ -55,6 +55,8 @@
 #include <inttypes.h>
 #include <crypt.h>
 
+#include <dlfcn.h>
+
 #define NGX_ALIGNMENT  _MAX_ALIGNMENT
 
 #include <ngx_auto_config.h>
diff --git a/src/os/win32/ngx_dlopen.c b/src/os/win32/ngx_dlopen.c
new file mode 100644
index 0000000..804f49d
--- /dev/null
+++ b/src/os/win32/ngx_dlopen.c
@@ -0,0 +1,22 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+char *
+ngx_dlerror(void)
+{
+    u_char         *p;
+    static u_char   errstr[NGX_MAX_ERROR_STR];
+
+    p = ngx_strerror(ngx_errno, errstr, NGX_MAX_ERROR_STR);
+    *p = '\0';
+
+    return (char *) errstr;
+}
diff --git a/src/os/win32/ngx_dlopen.h b/src/os/win32/ngx_dlopen.h
new file mode 100644
index 0000000..0d6b405
--- /dev/null
+++ b/src/os/win32/ngx_dlopen.h
@@ -0,0 +1,32 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#ifndef _NGX_DLOPEN_H_INCLUDED_
+#define _NGX_DLOPEN_H_INCLUDED_
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+#define NGX_HAVE_DLOPEN  1
+
+
+#define ngx_dlopen(path)           LoadLibrary((char *) path)
+#define ngx_dlopen_n               "LoadLibrary()"
+
+#define ngx_dlsym(handle, symbol)  (void *) GetProcAddress(handle, symbol)
+#define ngx_dlsym_n                "GetProcAddress()"
+
+#define ngx_dlclose(handle)        (FreeLibrary(handle) ? 0 : -1)
+#define ngx_dlclose_n              "FreeLibrary()"
+
+
+char *ngx_dlerror(void);
+
+
+#endif /* _NGX_DLOPEN_H_INCLUDED_ */