Passing --disable-static to ./configure breaks examples compilation

[abustany]

From the current (1.9.0) release:

$ NOCONFIGURE=1 ./autogen.sh
$ ./configure --disable-static
$ make -j8
... lots of logs ...

../src/websocket.c:15:10: fatal error: websocket.h: No such file or directory
   15 | #include "websocket.h"
      |          ^~~~~~~~~~~~~

Removing --disable-static fixes the build.

[lf-]

The reason for this is that the build products are reused from src in the case of NOT --disable-static and --disable-dep-track. From what I can tell, make winds up hitting an implicit rule to build the ../src/websocket.c because of ../src/websocket.o:

examples/Makefile.am:

ws_echo2_LDADD = \
    ../src/base64.o \
    ../src/char_buffer.o \
    ../src/hash_table.o \
    ../src/sha1.o \
    ../src/socket_manager.o \
    ../src/websocket.o

In the case of the Nix build, we are adding --disable-static and --disable-dep-track due to setup.sh defaults. Interestingly, enabling dep tracking plus disabled static outputs creates a different and interesting issue with a .Tpo file being reported as missing.

Somewhere in here is a misuse of autotools, but I don't know enough about autotools to identify what it is.