diff --git a/tools/winebuild/build.h b/tools/winebuild/build.h
index c100b2cda9f..a899a1e424d 100644
--- a/tools/winebuild/build.h
+++ b/tools/winebuild/build.h
@@ -85,6 +85,7 @@ typedef struct
 
 typedef struct
 {
+    char            *src_name;           /* file name of the source spec file */
     char            *file_name;          /* file name of the dll */
     char            *dll_name;           /* internal name of the dll */
     char            *init_func;          /* initialization routine */
@@ -214,6 +215,7 @@ extern int display_warnings;
 extern int kill_at;
 extern int verbose;
 extern int save_temps;
+extern int link_ext_symbols;
 
 extern char *input_file_name;
 extern char *spec_file_name;
diff --git a/tools/winebuild/import.c b/tools/winebuild/import.c
index 7eafe4778f9..7f228e53265 100644
--- a/tools/winebuild/import.c
+++ b/tools/winebuild/import.c
@@ -440,8 +440,25 @@ static void check_undefined_exports( DLLSPEC *spec )
         if (odp->flags & FLAG_FORWARD) continue;
         if (find_name( odp->link_name, &undef_symbols ))
         {
-            odp->flags |= FLAG_EXT_LINK;
-            add_name( &ext_link_imports, odp->link_name );
+            switch(odp->type)
+            {
+            case TYPE_PASCAL:
+            case TYPE_STDCALL:
+            case TYPE_CDECL:
+            case TYPE_VARARGS:
+                if (link_ext_symbols)
+                {
+                    odp->flags |= FLAG_EXT_LINK;
+                    add_name( &ext_link_imports, odp->link_name );
+                }
+                else error( "%s:%d: function '%s' not defined\n",
+                            spec->src_name, odp->lineno, odp->link_name );
+                break;
+            default:
+                error( "%s:%d: external symbol '%s' is not a function\n",
+                       spec->src_name, odp->lineno, odp->link_name );
+                break;
+            }
         }
     }
 }
diff --git a/tools/winebuild/main.c b/tools/winebuild/main.c
index 98da64376fd..87625e9d8ab 100644
--- a/tools/winebuild/main.c
+++ b/tools/winebuild/main.c
@@ -47,6 +47,7 @@ int display_warnings = 0;
 int kill_at = 0;
 int verbose = 0;
 int save_temps = 0;
+int link_ext_symbols = 0;
 
 #ifdef __i386__
 enum target_cpu target_cpu = CPU_x86;
@@ -246,8 +247,9 @@ static const char usage_str[] =
 "       --as-cmd=AS          Command to use for assembling (default: as)\n"
 "   -d, --delay-lib=LIB      Import the specified library in delayed mode\n"
 "   -D SYM                   Ignored for C flags compatibility\n"
-"   -E, --export=FILE        Export the symbols defined in the .spec or .def file\n"
 "   -e, --entry=FUNC         Set the DLL entry point function (default: DllMain)\n"
+"   -E, --export=FILE        Export the symbols defined in the .spec or .def file\n"
+"       --external-symbols   Allow linking to external symbols\n"
 "   -f FLAGS                 Compiler flags (only -fPIC is supported)\n"
 "   -F, --filename=DLLFILE   Set the DLL filename (default: from input file name)\n"
 "   -h, --help               Display this help message\n"
@@ -285,6 +287,7 @@ enum long_options_values
     LONG_OPT_DEF,
     LONG_OPT_EXE,
     LONG_OPT_ASCMD,
+    LONG_OPT_EXTERNAL_SYMS,
     LONG_OPT_LDCMD,
     LONG_OPT_NMCMD,
     LONG_OPT_RELAY16,
@@ -299,18 +302,19 @@ static const char short_options[] = "C:D:E:F:H:I:K:L:M:N:d:e:f:hi:kl:m:o:r:u:vw"
 
 static const struct option long_options[] =
 {
-    { "dll",      0, 0, LONG_OPT_DLL },
-    { "def",      0, 0, LONG_OPT_DEF },
-    { "exe",      0, 0, LONG_OPT_EXE },
-    { "as-cmd",   1, 0, LONG_OPT_ASCMD },
-    { "ld-cmd",   1, 0, LONG_OPT_LDCMD },
-    { "nm-cmd",   1, 0, LONG_OPT_NMCMD },
-    { "relay16",  0, 0, LONG_OPT_RELAY16 },
-    { "relay32",  0, 0, LONG_OPT_RELAY32 },
-    { "save-temps",0, 0, LONG_OPT_SAVE_TEMPS },
-    { "subsystem",1, 0, LONG_OPT_SUBSYSTEM },
-    { "target",   1, 0, LONG_OPT_TARGET },
-    { "version",  0, 0, LONG_OPT_VERSION },
+    { "dll",           0, 0, LONG_OPT_DLL },
+    { "def",           0, 0, LONG_OPT_DEF },
+    { "exe",           0, 0, LONG_OPT_EXE },
+    { "as-cmd",        1, 0, LONG_OPT_ASCMD },
+    { "external-symbols", 0, 0, LONG_OPT_EXTERNAL_SYMS },
+    { "ld-cmd",        1, 0, LONG_OPT_LDCMD },
+    { "nm-cmd",        1, 0, LONG_OPT_NMCMD },
+    { "relay16",       0, 0, LONG_OPT_RELAY16 },
+    { "relay32",       0, 0, LONG_OPT_RELAY32 },
+    { "save-temps",    0, 0, LONG_OPT_SAVE_TEMPS },
+    { "subsystem",     1, 0, LONG_OPT_SUBSYSTEM },
+    { "target",        1, 0, LONG_OPT_TARGET },
+    { "version",       0, 0, LONG_OPT_VERSION },
     /* aliases for short options */
     { "delay-lib",     1, 0, 'd' },
     { "export",        1, 0, 'E' },
@@ -466,6 +470,9 @@ static char **parse_options( int argc, char **argv, DLLSPEC *spec )
         case LONG_OPT_ASCMD:
             as_command = xstrdup( optarg );
             break;
+        case LONG_OPT_EXTERNAL_SYMS:
+            link_ext_symbols = 1;
+            break;
         case LONG_OPT_LDCMD:
             ld_command = xstrdup( optarg );
             break;
@@ -554,6 +561,7 @@ static int parse_input_file( DLLSPEC *spec )
     char *extension = strrchr( spec_file_name, '.' );
     int result;
 
+    spec->src_name = xstrdup( input_file_name );
     if (extension && !strcmp( extension, ".def" ))
         result = parse_def_file( input_file, spec );
     else
diff --git a/tools/winebuild/winebuild.man.in b/tools/winebuild/winebuild.man.in
index 78e10a295f0..3b6d0c77161 100644
--- a/tools/winebuild/winebuild.man.in
+++ b/tools/winebuild/winebuild.man.in
@@ -85,6 +85,14 @@ Specify a .spec file (see \fBSPEC FILE SYNTAX\fR for details),
 or a standard Windows .def file that defines the exports
 of the DLL or executable that is being built.
 .TP
+.B \--external-symbols
+Allow linking to external symbols directly from the spec
+file. Normally symbols exported by a dll have to be defined in the dll
+itself; this option makes it possible to use symbols defined in
+another Unix library (for symbols defined in another dll, a
+.I forward
+specification must be used instead).
+.TP
 .BI \-f\  flags
 Ignored for compatibility with the C compiler.
 .TP