Support building sqlite3 from amalgamation

[cole-miller]

This adds a --enable-build-sqlite option to our configure.ac. In this mode, the build will look for sqlite3.c in the build root and just add that to libdqlite_la_SOURCES, instead of linking with -lsqlite3.

The build system doesn't take care of fetching the SQLite amalgamation -- the idea is to obtain an SQLite source archive/checkout and do make sqlite3.c, or download the amalgamation from sqlite.org. It's important to use a version of the amalgamation that matches the version of sqlite.h that's on your include path.

Our build turns on a bunch of warnings that fire on the SQLite source code; I had to modify the amalgamation by adding

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsign-conversion"
#pragma GCC diagnostic ignored "-Wconversion"
#pragma GCC diagnostic ignored "-Wfloat-equal"
#pragma GCC diagnostic ignored "-Wfloat-conversion"
#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"

at the top and

#pragma GCC diagnostic pop

at the bottom.

The point is to be able to easily add printfs in SQLite code, turn on SQLITE_DEBUG, etc., to support debugging issues like #432 that arise from the interaction between SQLite and our VFS.

Signed-off-by: Cole Miller cole.miller@canonical.com

[codecov]

Codecov Report

Merging #444 (0da0e65) into master (89ca093) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #444   +/-   ##
=======================================
  Coverage   74.47%   74.47%           
=======================================
  Files          32       32           
  Lines        5382     5382           
  Branches     1682     1682           
=======================================
  Hits         4008     4008           
- Misses        817      818    +1     
+ Partials      557      556    -1     

Impacted Files	Coverage Δ
src/gateway.c	60.41% <0.00%> (ø)

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[cole-miller]

Oh, if you -DSQLITE_DEBUG there are more warnings to disable.

#pragma GCC diagnostic ignored "-Wsign-conversion"
#pragma GCC diagnostic ignored "-Wconversion"
#pragma GCC diagnostic ignored "-Wfloat-equal"
#pragma GCC diagnostic ignored "-Wfloat-conversion"
#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#pragma GCC diagnostic ignored "-Wsign-compare"
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"

[MathieuBordere]

Cool, should come in handy

[MathieuBordere]

can you fix the merge conflict please @cole-miller ?