tool/cosmocc: Allow exceptions and rtti (#1074)

With `libunwind` and `libcxxabi` included in `libcosmo`, we can now
allow users to build C++ applications with exceptions and RTTI enabled.

The default is still disabling these two to avoid bloating the binary.

Closes #1065

Author: trungnt2910

tool/cosmocc/bin/cosmocc

@@ -151,11 +151,9 @@ for x; do
   elif [ x"$x" = x"-r" ] ||
        [ x"$x" = x"-S" ] ||
        [ x"$x" = x"-pie" ] ||
-       [ x"$x" = x"-frtti" ] ||
        [ x"$x" = x"-shared" ] ||
        [ x"$x" = x"-nostdlib" ] ||
        [ x"$x" = x"-mred-zone" ] ||
-       [ x"$x" = x"-fexceptions" ] ||
        [ x"$x" = x"-fsanitize=thread" ]; then
     fatal_error "$x flag not supported"
   elif [ x"$x" = x"-mno-red-zone" ]; then

tool/cosmocc/bin/cosmocross

@@ -142,11 +142,9 @@ for x; do
     continue
   elif [ x"$x" = x"-r" ] ||
        [ x"$x" = x"-pie" ] ||
-       [ x"$x" = x"-frtti" ] ||
        [ x"$x" = x"-shared" ] ||
        [ x"$x" = x"-nostdlib" ] ||
        [ x"$x" = x"-mred-zone" ] ||
-       [ x"$x" = x"-fexceptions" ] ||
        [ x"$x" = x"-fsanitize=thread" ]; then
     echo "$PROG: $x not supported" >&2
     exit 1