Build fails with FLB_AWS=OFF and FLB_SIGNV4=OFF

[tonobo]

Building without AWS support fails in src/flb_http_client.c.

This happens with v5.0.6 and current master at be271c2.

To reproduce on that commit, use a fresh build directory:

cmake -S . -B build -G Ninja \
  -DFLB_MINIMAL=ON -DFLB_AWS=OFF -DFLB_SIGNV4=OFF \
  -DFLB_CUSTOM_CALYPTIA=OFF -DFLB_KAFKA=OFF -DFLB_WASM=OFF \
  -DFLB_ZIG=OFF -DFLB_RIPSER=OFF \
  -DFLB_IN_HTTP=ON -DFLB_OUT_HTTP=ON \
  -DFLB_SHARED_LIB=OFF -DFLB_EXAMPLES=OFF
cmake --build build --target fluent-bit

The build fails with:

src/flb_http_client.c:2515:25: warning: implicit declaration of function 'flb_upstream_ha_node_get'
src/flb_http_client.c:2521:33: error: invalid use of undefined type 'struct flb_upstream_node'
src/flb_http_client.c:2523:57: error: invalid use of undefined type 'struct flb_upstream_node'

The build should work with AWS support disabled.

Adding this include to src/flb_http_client.c fixed the v5.0.6 build with both options still disabled:

#include <fluent-bit/flb_upstream_ha.h>

Related: #9664 and #10323. Both were closed as stale, but the error is still present.