use the faster headers-only mode for diff3

ok stsp@

ok stsp@

in_repo_path was used only to build a path, it's then assigned to path (which is NULL at that point.) Just asprintf into path. ok stsp@

ok stsp@

call got_get_repo_commit only once and avoid leaking the field of repo_commit at each loop iteration. ok stsp@

some code-paths may leak it. ok stsp@

it's still used a bit later, so defer the free'ing at the next loop iteration or at function end.

in case of a failure between when it's allocated and when it's released it might get leaked otherwise. ok and semplification stsp@

ok stsp@

ok stsp@

getchange() in diff3.c takes any line that starts with an integer and treats it as a hunk header. It doesn't actually require ed script instructions, and traditional ed script diff output would break it. Thus, changing Got's diff3 to rely on plain diff output mode paves the way for implementing traditional ed-script style output in diff.git. Patch by Tom Jones

in the loop of match_loose_object we allocate a string per directory entry that in some case it was free(3)'d before `continue' or `goto', but not always. Instead, use a more common idiom. ok stsp@

This removes the gcc ternary if extension (includes follow-up diff.git fix for missing '\' in wrapped macro 7a38b3a33f8b124c9c01da154dfdf711d328b01d)

ok stsp@

if strdup fails we fail to free the querystring Found by clang' scan-build.

dead store found by clang' scan-build.

In 95a4a5a1e8d0952ee0d2523dc31df7170d80e0b3 I forgot to fix the links for the favicons and the web manifest.

problem introduced in commit 625e5896fc9ecf87ccfc92ad2a65cd3be58f73c0

ok op@

got_get_repo_tags needs some tweaking to how tag_commit is allocated too. ok stsp@