Add a "fork" of musl as //fusl.

fusl/tools/add-cfi.common.awk

+function hex2int(str,   i) {
+  str = tolower(str)
+
+  for (i = 1; i <= 16; i++) {
+    char = substr("0123456789abcdef", i, 1)
+    lookup[char] = i-1
+  }
+
+  result = 0
+  for (i = 1; i <= length(str); i++) {
+    result = result * 16
+    char   = substr(str, i, 1)
+    result = result + lookup[char]
+  }
+  return result
+}
+
+function parse_const(str) {
+  sign = sub(/^-/, "", str)
+  hex  = sub(/^0x/, "", str)
+  if (hex)
+    n = hex2int(str)
+  else
+    n = str+0
+  return sign ? -n : n
+}