[beast: 24/28] BUILD: preserve user defined CFLAGS, CXXFLAGS, LDFLAGS

[Tim Janik <timj src gnome org>]

commit a8abb3f56082e0cacf6e9213085f435b0364169c
Author: Tim Janik <timj gnu org>
Date:   Tue Nov 24 14:17:10 2015 +0100

    BUILD: preserve user defined CFLAGS, CXXFLAGS, LDFLAGS
    
    Signed-off-by: Tim Janik <timj gnu org>

 configure.ac |   18 ++----------------
 1 files changed, 2 insertions(+), 16 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 2434fba..15e91f9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -155,9 +155,6 @@ else
 fi
 AC_SUBST(AM_LDFLAGS)
 
-# Pick C++ dialect, needed in CXXFLAGS for compile tests
-MC_CXX_TRY_OPTION(CXXFLAGS,  -std=gnu++0x)
-
 # AM_CFLAGS & AM_CXXFLAGS
 MC_CXX_TRY_OPTION(AM_CXXFLAGS,  -std=gnu++0x)
 BOTHCCXXFLAGS=
@@ -451,13 +448,9 @@ AC_DEFUN([AC_ASOUND_CHECK],
     dnl --- check for -lasound ---
     found_libasound=0
     dnl snd_asoundlib_version() was introduced in ALSA 1.0.5
-    cflags=$CFLAGS
-    ldflags=$LDFLAGS
-    CFLAGS=""
-    LDFLAGS=""
+    CFLAGS=""  # kept in saved_cflags
+    LDFLAGS="" # kept in saved_ldflags
     AC_CHECK_LIB(asound, snd_asoundlib_version, ALSA_LIBS="-lasound"; found_libasound=1)
-    CFLAGS="$cflags"
-    LDFLAGS="$ldflags"
     if test $found_libasound = 0; then
        AC_MSG_ERROR([ALSA version 1.0.5 is required to build this package])
     fi
@@ -676,13 +669,6 @@ AC_BEAST_REQUIREMENTS
 AC_SUIDMAIN_REQUIREMENTS
 AC_DOC_REQUIREMENTS
 
-# Automake @VARIABLE@ exports.
-AC_SUBST(CFLAGS)
-AC_SUBST(CXXFLAGS)
-AC_SUBST(CPPFLAGS)
-AC_SUBST(LDFLAGS)
-
-
 # create output files
 AC_CONFIG_FILES([
 Makefile