-AC_PATH_PROG(MAKE, make)
-AC_PATH_PROG(MKDEP, makedepend)
-AC_PATH_PROG(SED, sed)
+AC_CHECK_PROGS([MAKE], [gmake make])
+AC_PATH_PROG([MKDEP], [makedepend])
+AC_PATH_PROG([SED], [sed])
+
+MKDEP_OPTIONS=-fdepend
+dnl Ask gcc where it's keeping its secret headers
+if test "x$GCC" = xyes; then
+ GCC_INCLUDES=`$CC -print-file-name=include`
+ if test "x$GCC_INCLUDES" != x; then
+ MKDEP_OPTIONS="$MKDEP_OPTIONS -I$GCC_INCLUDES"
+ fi
+fi
+AC_SUBST([MKDEP_OPTIONS])
+
+dnl Check to see if dlopen is in default libraries (like Solaris, which
+dnl has it in libc), or if libdl is needed to get it.
+AC_CHECK_FUNC([dlopen], [],
+ [AC_CHECK_LIB([dl], [dlopen], [DLOPEN_LIBS="-ldl"])])