autotools: dont use newer AC_CHECK_INCLUDES_DEFAULT, don't quote AC_ERROR_MSG

configure.ac

@@ -488,13 +488,8 @@ dnl Back to "normal" configuring
 dnl **********************************************************************
 
 dnl Checks for header files.
-m4_warn([obsolete],
-[The preprocessor macro `STDC_HEADERS' is obsolete.
-  Except in unusual embedded environments, you can safely include all
-  ISO C90 headers unconditionally.])dnl
-# Autoupdate added the next two lines to ensure that your configure
-# script's behavior did not change.  They are probably safe to remove.
-AC_CHECK_INCLUDES_DEFAULT
+STDC_HEADERS
+
 AC_PROG_EGREP
 
 

m4/ax_code_coverage.m4

@@ -206,14 +206,14 @@ code-coverage-capture-hook:
 ])
 
 AC_DEFUN([_AX_CODE_COVERAGE_ENABLED],[
-	AX_CHECK_GNU_MAKE([],[AC_MSG_ERROR([not using GNU make that is needed for coverage])])
+	AX_CHECK_GNU_MAKE([],AC_MSG_ERROR([not using GNU make that is needed for coverage]))
 	AC_REQUIRE([AX_ADD_AM_MACRO_STATIC])
 	# check for gcov
 	AC_CHECK_TOOL([GCOV],
 		  [$_AX_CODE_COVERAGE_GCOV_PROG_WITH],
 		  [:])
 	AS_IF([test "X$GCOV" = "X:"],
-	      [AC_MSG_ERROR([gcov is needed to do coverage])])
+	      AC_MSG_ERROR([gcov is needed to do coverage]))
 	AC_SUBST([GCOV])
 
 	dnl Check if gcc is being used