Add header check for dlfcn.h.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.1@5678 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

configh.in

@@ -288,9 +288,10 @@
 #endif /* !HAVE_STRTOLL */
 
 /*
- * Do we have the dlsym() function?
+ * Do we have the dlsym() function and header?
  */
 
+#undef HAVE_DLFCN_H
 #undef HAVE_DLSYM
 
 /*

configure.in

@@ -440,6 +440,7 @@ AC_CHECK_FUNC(strtoll, AC_DEFINE(HAVE_STRTOLL))
 
 dnl Check for dlopen/dlsym...
 AC_SEARCH_LIBS(dlsym, dl, AC_DEFINE(HAVE_DLSYM))
+AC_CHECK_HEADER(dlfcn.h, AC_DEFINE(HAVE_DLFCN_H))
 
 dnl Check for audio libraries...
 AUDIOLIBS=""

src/glut_compatability.cxx

@@ -43,9 +43,9 @@
 #    define GLX_GLXEXT_LEGACY
 #    include <GL/glx.h>
 #  endif // HAVE_GLXGETPROCADDRESSARB
-#  ifdef HAVE_DLSYM
+#  ifdef HAVE_DLFCN_H
 #    include <dlfcn.h>
-#  endif // HAVE_DLSYM
+#  endif // HAVE_DLFCN_H
 #  define MAXWINDOWS 32
 static Fl_Glut_Window *windows[MAXWINDOWS+1];
 
@@ -443,7 +443,7 @@ GLUTproc glutGetProcAddress(const char *procName) {
 #  ifdef WIN32
   return (GLUTproc)wglGetProcAddress((LPCSTR)procName);
 
-#  elif defined(HAVE_DLSYM)
+#  elif defined(HAVE_DLSYM) && defined(HAVE_DLFCN_H)
   char symbol[1024];
 
   snprintf(symbol, sizeof(symbol), "_%s", procName);