add missing tests (some of them were implicit with older libtool versions)

[[Imported from SVN: r5407]]

m4/dune_common.m4

 AC_DEFUN([DUNE_COMMON_CHECKS],
 [
+  AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+
+  AC_REQUIRE([AC_PROG_CC])
   AC_REQUIRE([AC_PROG_CPP])
+  AC_REQUIRE([AC_PROG_CXX])
   AC_REQUIRE([AC_PROG_CXXCPP])
   AC_REQUIRE([AC_PROG_INSTALL])
   AC_REQUIRE([AC_PROG_LN_S])
   AC_REQUIRE([AC_PROG_MAKE_SET])
   AC_REQUIRE([AC_PROG_RANLIB])
   AC_REQUIRE([AC_PROG_LIBTOOL])
+  AC_REQUIRE([AC_PROG_AWK])
 
   AC_REQUIRE([DUNE_CHECK_COMPILER])
   AC_REQUIRE([GXX0X])