fix(r/sedonadb): Add -Wno-pedantic to avoid compile error

[yutannihilation]

Fix #164

Background

When -pedantic flag is passed via CFLAGS, the aws-lc-sys crate cannot be compiled. R CMD INSTALL is not the case, so the CI is fine without this. However, when using devtools or pak, this flag is passed via pkgbuild.

Why? Pkgbuild's comment says this flag is to "enforce good coding practice" to the R package developers. Also, it says this flag is used on CRAN check. But, considering this package doesn't strongly aim for CRAN (at least at the moment), probably it's fine to ignore the warnings.

https://github.com/r-lib/pkgbuild/blob/d88519a177c18c6a2701e1eaf9fb22d37f9580b9/R/compiler-flags.R#L3-L5

Details

This pull request simply tries to override -pedantic by -Wno-pedantic. In the current Makevars.win.in, I used substr to remove -pedantic flag. However, it seems appending this flag is simpler if this works.

Some more tweaks on Makevars.win.in:

• Replaced ALL_CPPFLAGS with CFLAGS. CPPFLAGS is C Pre-Processor flags, so I think CFLAGS is appropriate here.
• Remove outdated comment AWS_LC_SYS_CFLAGS

[paleolimbot]

Thank you!