commit 95f92d85ab374f99e3ebf07aa1669405421429d9
Author: Benjamin Lorenz <lorenz@math.tu-berlin.de>
Date:   Mon Aug 20 12:23:49 2018 +0200

    bundled/singular: remove -std={c,gnu}++{03,11,0x} from CXXFLAGS
    
    this overrides our c++14 flag and causes compilation errors (see #1090)
    
diff --git a/bundled/singular/support/configure.pl b/bundled/singular/support/configure.pl
index 57c79a8edc..d69aa37b0d 100644
--- a/bundled/singular/support/configure.pl
+++ b/bundled/singular/support/configure.pl
@@ -148,6 +148,9 @@ sub proceed {
    if (defined $Polymake::Configure::CLANGversion) {
       $CXXFLAGS .= " -Wno-deprecated-register";
    }
+
+   # remove old -std= versions from CXXFLAGS which would override our c++14
+   $CXXFLAGS =~ s/-std=(?:c|gnu)\+\+(?:11|0x|03)//g;
    
    $LIBS .= " -ldl" unless $LIBS =~ /-ldl/ or $^O ne "linux";