Hardcode couchjs binary name

Windows doesn't have the libgen.h header or an easily identified
basename function. Instead of playing games we just configure the name
with autoconf and run with that.

configure.ac

@@ -219,7 +219,12 @@ AC_CHECK_LIB([$JS_LIB_BASE], [JS_GetStringCharsAndLength],
 # Else, hope that 1.7.0 works
 LIBS="$OLD_LIBS"
 
+AC_DEFINE([COUCHJS_NAME], ["couchjs"], ["CouchJS executable name."])
+
 if test x${IS_WINDOWS} = xTRUE; then
+
+    AC_DEFINE([COUCHJS_NAME], ["couchjs.exe"], ["CouchJS executable name."])
+
     if test -f "$JS_LIB_DIR/$JS_LIB_BASE.dll"; then
         # seamonkey 1.7- build layout on Windows
         JS_LIB_BINARY="$JS_LIB_DIR/$JS_LIB_BASE.dll"

src/couchdb/priv/couch_js/help.h

@@ -13,8 +13,6 @@
 #ifndef COUCHJS_HELP_H
 #define COUCHJS_HELP_H
 
-#include <libgen.h>
-
 #include "config.h"
 
 static const char VERSION_TEMPLATE[] =
@@ -55,7 +53,7 @@ static const char USAGE_TEMPLATE[] =
     "\n"
     "Report bugs at <%s>.\n";
 
-#define BASENAME basename((char*)argv[0])
+#define BASENAME COUCHJS_NAME
 
 #define couch_version(basename)  \
     fprintf(                     \