more natural naming

build/bin/sage-build-env-config.in

@@ -33,16 +33,16 @@ fi
 
 # The configured compilation flags.
 if [ "x$CFLAGS" == "x" ]; then
-    export CFLAGS="@ORIGINAL_CFLAGS@"
+    export CFLAGS="@CFLAGS@"
 fi
 if [ "x$CXXFLAGS" == "x" ]; then
-    export CXXFLAGS="@ORIGINAL_CXXFLAGS@"
+    export CXXFLAGS="@CXXFLAGS@"
 fi
 if [ "x$FCFLAGS" == "x" ]; then
-    export FCFLAGS="@ORIGINAL_FCFLAGS@"
+    export FCFLAGS="@FCFLAGS@"
 fi
 if [ "x$F77FLAGS" == "x" ]; then
-    export F77FLAGS="@ORIGINAL_F77FLAGS@"
+    export F77FLAGS="@F77FLAGS@"
 fi
 
 # This is usually blank if the system GMP is used, or $SAGE_LOCAL otherwise

configure.ac

@@ -313,10 +313,10 @@ AX_PROG_PERL_VERSION([5.8.0],[],[
 ###############################################################################
 
 # Save compiler flags as configured by the user.
-AC_SUBST(ORIGINAL_CFLAGS, "$CFLAGS")
-AC_SUBST(ORIGINAL_CXXFLAGS, "$CXXFLAGS")
-AC_SUBST(ORIGINAL_FCFLAGS, "$FCFLAGS")
-AC_SUBST(ORIGINAL_F77FLAGS, "$F77FLAGS")
+AC_SUBST(CFLAGS, "$CFLAGS")
+AC_SUBST(CXXFLAGS, "$CXXFLAGS")
+AC_SUBST(FCFLAGS, "$FCFLAGS")
+AC_SUBST(F77FLAGS, "$F77FLAGS")
 
 SAGE_CHECK_CONDA_COMPILERS