-my $ecc = $target{cc};
-if ($^O ne "VMS" && !$disabled{makedepend}) {
- # Is the compiler gcc or clang? $ecc is used below to see if
- # error-checking can be turned on.
- my $ccpcc = "$config{cross_compile_prefix}$target{cc}";
- open(PIPE, "$ccpcc --version 2>&1 |");
- my $lines = 2;
- while ( <PIPE> ) {
- # Find the version number and save the major.
- m|(?:.*)\b(\d+)\.\d+\.\d+\b(?:.*)|;
- my $compiler_major = $1;
- # We know that GNU C version 3 and up as well as all clang
- # versions support dependency generation
- $config{makedepprog} = $ccpcc
- if (/clang/ || (/gcc/ && $compiler_major >= 3));
- $ecc = "clang" if /clang/;
- $ecc = "gcc" if /gcc/;
- last if ($config{makedepprog} || !$lines--);
+my %predefined;
+
+if ($^O ne "VMS") {
+ my $cc = "$config{cross_compile_prefix}$target{cc}";
+
+ # collect compiler pre-defines from gcc or gcc-alike...
+ open(PIPE, "$cc -dM -E -x c /dev/null 2>&1 |");
+ while (<PIPE>) {
+ m/^#define\s+(\w+(?:\(\w+\))?)(?:\s+(.+))?/ or last;
+ $predefined{$1} = $2 // "";