Signing a transaction with openSSL
While I haven't verified the signature, upon inspection of the encoding I think I can see what is wrong. Let's break down the scriptSig briefly and I'll show you:

8a (total number of bytes to follow)
46 (the signature is 0x46 bytes long *THIS IS WHERE THE ISSUE IS*)
30 (compound DER type)
44 (0x44 bytes following)
02 (integer type)
20 (0x20 bytes long)
3c8aaa41ae647149f70ce24f73109e99d59d7e54a5d854239943358d581e9f83 (R value)
02 (integer type)
20 (0x20 bytes long)
6336cb57c00bb78f46c881b3d6bb2ed76dc652eedf36064ae022ea4ae3ba3b10 (S value)
01 (SIGHASH_ALL sighash type)
41 (length of public key is 0x41 bytes)
049d0f70eed85345ca5c1c04563bed19608562c37d644061785a836e8f199155f2818a1e2661f9ed501d8f906611892099a9de5a7ea9f641ecb4dd75bbb63c2d5a (public key)


Now I've highlighted the length of the DER encoded signature as the issue - 46. This should be 47. The reason is that that length is actually supposed to be the length of the signature plus one byte for the sighash type. Unlike normal DER signature produced by OpenSSL, Bitcoin requires the sighash type to be appended, in this case 01 for SIGHASH_ALL. You can see the 01 byte present. But you haven't updated the length. In the valid transaction below it, on the other hand, you can see the length is 47 despite the fields being the same length.

So try updating the 46 to a 47 and see if it works :)