Namely, define it if only `MG_ENABLE_HTTP_STREAMING_MULTIPART` and
`MG_ENABLE_FILESYSTEM` are on

PUBLISHED_FROM=3094738a4b76ceb09a3c2374e8d9d914b71c3441

PUBLISHED_FROM=2f6fb7ea5abdcd4ca9b06956172938ee3bc28459

And use it for `FW_ARCHITECTURE`. This is needed because with
Microchip's xc32, `-DFOO=\"bar\"` results in `FOO` being `bar`, not
`"bar"`, so we have to stringify differently.

PUBLISHED_FROM=d0aeebb55ef9e0e92a7f750104cd6600e0d9c636

PUBLISHED_FROM=bd87b901b7c1c1a4f9b0f875f0b024b672121d4a

PUBLISHED_FROM=6abc158f198f5bd032e5ab06cc0ba3373434cdbe

On PIC32MZ, this is required to get `ntohl` and friends.

PUBLISHED_FROM=82ab532cd3757df6f79215f3eaca90cd87f6c965

PUBLISHED_FROM=5b63325ade34b9032476fc88ac407816990f1cfc

PUBLISHED_FROM=e6fb19c5256b6d43359f21b325e16b415152f26f

PUBLISHED_FROM=26becdaf7dd61481b88b166ea87d44a7bc796660

Also performs trnasparent SPIFFS -> SLFS cert copy.

If the file's extension is .pem, convert it to DER format and put on SLFS.

PUBLISHED_FROM=364caab21969ca28a05802c4dde93a11d1e0feda

Also fixed a memory leak on reconnect: previously, each reconnect was
creating a `struct mg_connection` which was never reclaimed

PUBLISHED_FROM=eefdcf557e032ac81d5ed3aba55ac912e400148e

PUBLISHED_FROM=b17ef5bc8ec801fca91c89af5f97767a55911952

PUBLISHED_FROM=ac54bcbc81a9ee688e8b90e261172be76a9fbacd

PUBLISHED_FROM=ea64670e42ae58bbe26abee5d928f2afcd83bd46

PUBLISHED_FROM=f1a804466bea6d6d77103525d76ef7b819b63477

PUBLISHED_FROM=cccd28ef43ec4e08fa52340ce78bda10db5ac27a

PUBLISHED_FROM=182c43c3bd82190cb816c8ebaddccc13a94950d0

PUBLISHED_FROM=0454cdeec5c7120eb4bf905fdd5b7abdcb4003c2

PUBLISHED_FROM=196199fd02ec9b20d1e76d1414bfafa624f9ebce

PUBLISHED_FROM=edb1063d3fd64e3c732f16b8bf101c065cdacddd

Currently only OpenSSL API impl, but the plan is to add more.

PUBLISHED_FROM=c85b26fa2312047768bdcf3eca583e60862aba90

PUBLISHED_FROM=8b5c6f70d5582402f327c4da7baee7cc15ee13aa

PUBLISHED_FROM=f554cc63dfea12455fe5e428c6ce5f3152774f8e

PUBLISHED_FROM=39a1c2a271c5cd961670e11c830105c17ba0b2e4

PUBLISHED_FROM=3ee9478275c4b9253b1dd4f98a69cecc89290bce

PUBLISHED_FROM=f03b963aaec02574e47c28ee8033551440b94f2d

PUBLISHED_FROM=2b82f3793b3c6d0cf1266e4cc0e67930f43002c5

PUBLISHED_FROM=46496c2d5340a0bbe4fe1c6c9ff187bc65d2d35f

PUBLISHED_FROM=774764f9d316e111912dae1fcaf2933141c59a60

Now all warnings are disabled on SDK files, and enabled on our
application's files.

Fixed a couple of things in nRF52 which were unnoticed because all
warnings were disabled there from the beginning.

PUBLISHED_FROM=a33ab22d0ce85efea364b80478986b88f4b0a3a2

PUBLISHED_FROM=f8b4e8650d72c2ec5525e0510fbc8a80f8645a14

Now it works in hardware.

PUBLISHED_FROM=f223bde2d2bebe97513ce073eb887552bc3d93af

PUBLISHED_FROM=cded8f36e2833e7c256ba6cbca0ebf1f6012dee7

PUBLISHED_FROM=79d3bc5ba7887e2126b64d2ea804c62606264ce2

PUBLISHED_FROM=c3d59657adff247f565bf0be59192e32d5d0bbf6

PUBLISHED_FROM=2a76ccddb62b63caeaca3785a07d7d0b94125eaf

PUBLISHED_FROM=3caea25dec11260561349fa096547bd62ecdb509

Also, do not require -DRTOS_SDK and pick socket/low-level event manager
based on LWIP_SOCKET.

PUBLISHED_FROM=d4afbdf8dab62a1c6ac4ca075c4a58887223dba4

PUBLISHED_FROM=d6ed793313a98545d5a89faafc8526b658ffff66

PUBLISHED_FROM=6455082726781aab819a7f8645e81adaa7fc7669