+# Define NO_STRCASESTR if you don't have strcasestr.
+#
+# Define NO_OPENSSL to disable linking with OpenSSL and use bundled SHA1
+# implementation (slower).
+#
+# Define NEEDS_LIBICONV if linking with libc is not enough (eg. Darwin).
+#
+# Define NO_C99_FORMAT if your formatted IO functions (printf/scanf et.al.)
+# do not support the 'size specifiers' introduced by C99, namely ll, hh,
+# j, z, t. (representing long long int, char, intmax_t, size_t, ptrdiff_t).
+# some C compilers supported these specifiers prior to C99 as an extension.
+#