Please Consider Increasing SECMEM_BUFFER_SIZE To 1048576

[Matthew Summers]

Hello,

I just got to testing on 2.2.x and I have had to increase the
SECMEM_BUFFER_SIZE to 2097152 to pass my trivial 100 proc concurrency
test with 100% reliability.

To remind about the test, using a 4096bit RSA key with id test at example.com

$ echo "test" | gpg -aer test at example.com -o gpg.txt

$ yes gpg.txt | head -100 | xargs -n 1 -P 5 gpg --decrypt -q  # 5

$ yes gpg.txt | head -100 | xargs -n 1 -P 10 gpg --decrypt -q   # 10

$ yes gpg.txt | head -100 | xargs -n 1 -P 100 gpg --decrypt -q  # 100