diff -ru fluxbox-1.0.0.orig/src/FbTk/FbString.cc fluxbox-1.0.0/src/FbTk/FbString.cc
--- fluxbox-1.0.0.orig/src/FbTk/FbString.cc	2008-03-11 10:36:10 +0100
+++ fluxbox-1.0.0/src/FbTk/FbString.cc	2008-03-11 10:39:29 +0100
@@ -46,7 +46,16 @@
 #ifdef HAVE_ICONV
 #include <iconv.h>
 #endif // HAVE_ICONV
+
+#if defined(__INTERIX)
+extern "C" {
+// interix has a broken langinfo.h without extern "C"
+#include <langinfo.h>
+}
+#else
 #include <langinfo.h>
+#endif
+
 #include <locale.h>
 
 #include <iostream>
diff -ru fluxbox-1.0.0.orig/src/FbTk/Font.cc fluxbox-1.0.0/src/FbTk/Font.cc
--- fluxbox-1.0.0.orig/src/FbTk/Font.cc	2008-03-11 10:36:10 +0100
+++ fluxbox-1.0.0/src/FbTk/Font.cc	2008-03-11 10:39:44 +0100
@@ -68,7 +68,15 @@
 #include <list>
 #include <map>
 #include <typeinfo>
+
+#if defined(__INTERIX)
+extern "C" {
+// interix has a broken langinfo.h without extern "C"
+#include <langinfo.h>
+}
+#else
 #include <langinfo.h>
+#endif
 
 #include <errno.h>